ORCID Profile
0000-0003-4033-4518
Current Organisation
Consejo Superior de Investigaciones Cientificas
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Atomic, Molecular, Nuclear, Particle and Plasma Physics | Atomic and Molecular Physics | Medical Physics | Transport Properties and Non-Equilibrium Processes | Nuclear Medicine |
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in the Physical Sciences | Diagnostic Methods | Expanding Knowledge in the Biological Sciences | Expanding Knowledge in the Medical and Health Sciences
Related Links
Publications
An experimental and theoretical investigation into the electronically excited states of para-benzoquinone
Publisher: AIP Publishing
Date: 09-05-2017
DOI: 10.1063/1.4982940
Abstract: We report on a combination of experimental and theoretical investigations into the structure of electronically excited para-benzoquinone (pBQ). Here synchrotron photoabsorption measurements are reported over the 4.0–10.8 eV range. The higher resolution obtained reveals previously unresolved pBQ spectral features. Time-dependent density functional theory calculations are used to interpret the spectrum and resolve discrepancies relating to the interpretation of the Rydberg progressions. Electron-impact energy loss experiments are also reported. These are combined with elastic electron scattering cross section calculations performed within the framework of the independent atom model–screening corrected additivity rule plus interference (IAM-SCAR + I) method to derive differential cross sections for electronic excitation of key spectral bands. A generalized oscillator strength analysis is also performed, with the obtained results demonstrating that a cohesive and reliable quantum chemical structure and cross section framework has been established. Within this context, we also discuss some issues associated with the development of a minimal orbital basis for the single configuration interaction strategy to be used for our high-level low-energy electron scattering calculations that will be carried out as a subsequent step in this joint experimental and theoretical investigation.
Excitation of electronic states in tetrahydrofuran by electron impact
Publisher: AIP Publishing
Date: 08-04-2011
DOI: 10.1063/1.3575454
Abstract: We report on differential and integral cross section measurements for the electron impact excitation of the three lowest lying Rydberg bands of electronic states in tetrahydrofuran. The energy range of the present experiments was 15–50 eV with the angular range of the differential cross section measurements being 15°–90°. The important effects of the long-range target dipole moment and the target dipole polarizability, on the scattering dynamics of this system, are evident from the present results. To the best of our knowledge, there are no other theoretical or experimental data against which we can compare the cross section results from this study.
Differential cross sections for the electron impact excitation of pyrimidine
Publisher: AIP Publishing
Date: 15-08-2012
DOI: 10.1063/1.4743961
Abstract: We report on differential cross section (DCS) measurements for the electron-impact excitation of the electronic states of pyrimidine. The energy range of the present measurements was 15–50 eV with the angular range of the measurements being 10°–90°. All measured DCSs displayed forward-peaked angular distributions, consistent with the relatively large magnitudes for the dipole moment and dipole polarizability of pyrimidine. Excitations to triplet states were found to be particularly important in some energy loss features at the lower incident electron energies. To the best of our knowledge there are no other experimental data or theoretical computations against which we can compare the present results.
Differential and integral electron scattering cross sections from tetrahydrofuran (THF) over a wide energy range: 1–10 000 eV
Publisher: Springer Science and Business Media LLC
Date: 06-2014
Total cross section measurements for electron scattering from dichloromethane
Publisher: AIP Publishing
Date: 26-12-2018
DOI: 10.1063/1.5080636
Abstract: Using our magnetically confined electron transmission apparatus, we report the results of total cross sections (TCSs) for electron scattering from dichloromethane (CH2Cl2). The energy range of this study is 1–300 eV. Wherever possible, the present data are compared to earlier measured TCSs of Wan et al. [J. Chem. Phys. 94, 1865 (1991)] and Karwasz et al. [Phys. Rev. A 59, 1341 (1999)] and to the corresponding theoretical independent atom model with screening corrected additivity rule and interference term (IAM-SCAR+I) results of Krupa et al. [Phys. Rev. A 97, 042702 (2018)] and a spherical complex optical potential formulation calculation of Naghma et al. [J. Electron Spectrosc. Relat. Phenom. 193, 48 (2014)]. Within their respective uncertainties, the present TCS and those of Karwasz et al. are found to be in very good agreement over their common energy range. However, agreement with the results of Wan et al. is quite poor. The importance of the experimentally inherent ‘missing angle’ effect (see later) on the measured TCS is investigated and found to be significant at the lower energies studied. Indeed, when this effect is accounted for, agreement between our measured TCSs and the corrected IAM-SCAR+I+rotations calculation results are, for energies above about 3 eV, in good accord (to better than 8%). Finally, we observe two σ* shape resonances, consistent with the earlier electron transmission spectroscopy results of Burrow et al. [J. Chem. Phys. 77, 2699 (1982)], at about 2.8 eV and 4.4 eV incident electron energy, in our measured TCS.
Cross sections for electron scattering from α
Publisher: Elsevier BV
Date: 07-2014
Electron impact excitation of the ã 3B1u electronic state in C2H4: An experimentally benchmarked system?
Publisher: AIP Publishing
Date: 11-05-2012
DOI: 10.1063/1.4716184
Abstract: We report on differential and integral cross section measurements for the electron impact excitation of the lowest-lying triplet electronic state (ã 3B1u) in ethylene (C2H4). The energy range of the present experiments was 9 eV–50 eV, with the angular range of the differential cross section measurements being 15°–90°. As the ground electronic state of C2H4 is a 1Ag state, this singlet → triplet excitation process is expected to be dominated by exchange scattering. The present angular distributions are found to support that assertion. Comparison, where possible, with previous experimental results from the University of Fribourg group shows very good agreement, to within the uncertainties on the measured cross sections. Agreement with the available theories, however, is generally marginal with the theories typically overestimating the magnitude of the differential cross sections. Notwithstanding that, the shapes of the theoretical angular distributions were in fact found to be in good accord with the corresponding experimental results.
Positron and electron collisions with nitrous oxide: Measured and calculated cross sections
Publisher: American Physical Society (APS)
Date: 23-02-2013
Positron kinetics in an idealized PET environment
Publisher: Springer Science and Business Media LLC
Date: 06-08-2015
DOI: 10.1038/SREP12674
Abstract: The kinetic theory of non-relativistic positrons in an idealized positron emission tomography PET environment is developed by solving the Boltzmann equation, allowing for coherent and incoherent elastic, inelastic, ionizing and annihilating collisions through positronium formation. An analytic expression is obtained for the positronium formation rate, as a function of distance from a spherical source, in terms of the solutions of the general kinetic eigenvalue problem. Numerical estimates of the positron range - a fundamental limitation on the accuracy of PET, are given for positrons in a model of liquid water, a surrogate for human tissue. Comparisons are made with the ‘gas-phase’ assumption used in current models in which coherent scattering is suppressed. Our results show that this assumption leads to an error of the order of a factor of approximately 2, emphasizing the need to accurately account for the structure of the medium in PET simulations.
Cross Sections for Positron Impact with 2,2,4-Trimethylpentane
Publisher: American Chemical Society (ACS)
Date: 11-04-2014
DOI: 10.1021/JP502632M
Abstract: 2,2,4-Trimethylpentane (C8H18), a hydrocarbon produced all over the world on a large scale in the processing of crude oil, has long been known and used in the energy sector. It has also recently attracted the attention of the radiation physics and chemistry community, owing to its applications in medical imaging techniques. Charged-particle interactions with this species unfortunately remain mostly unknown. In this study, we report on measured total cross sections for positron scattering from 2,2,4-trimethylpentane in the energy range from 0.12 to 50 eV. We also present calculations of the total cross sections, elastic integral and differential cross sections, positronium formation cross sections, and inelastic integral cross sections at energies from 1 to 1000 eV using the independent atom model with screening corrected additivity rule. A knowledge of those scattering cross sections might, through simulation models, help to improve the accuracy of current radiation detection devices and hence provide better estimates of the extent of any charged-particle-induced damage in biomolecular systems.
A comparison of experimental and theoretical low energy positron scattering from furan
Publisher: AIP Publishing
Date: 22-12-0019
DOI: 10.1063/5.0027874
Abstract: This paper presents a joint experimental and theoretical study of positron scattering from furan. Experimental data were measured using the low energy positron beamline located at the Australian National University and cover an energy range from 1 eV to 30 eV. Cross sections were measured for total scattering, total elastic and inelastic scattering, positronium formation, and differential elastic scattering. Two theoretical approaches are presented: the Schwinger multichannel method and the independent atom method with screening corrected additivity rule. In addition, our data are compared to corresponding electron scattering results from the same target with a number of significant differences observed and discussed.
Integral cross sections for electron impact excitation of vibrational and electronic states in phenol
Publisher: AIP Publishing
Date: 19-05-2015
DOI: 10.1063/1.4921313
Abstract: We report on measurements of integral cross sections (ICSs) for electron impact excitation of a series of composite vibrational modes and electronic-states in phenol, where the energy range of those experiments was 15–250 eV. There are currently no other results against which we can directly compare those measured data. We also report results from our independent atom model with screened additivity rule correction computations, namely, for the inelastic ICS (all discrete electronic states and neutral dissociation) and the total ionisation ICS. In addition, for the relevant dipole-allowed excited electronic states, we also report f-scaled Born-level and energy-corrected and f-scaled Born-level (BEf-scaled) ICS. Where possible, our measured and calculated ICSs are compared against one another with the general level of accord between them being satisfactory to within the measurement uncertainties.
A Relativistic Complex Optical Potential Calculation for Electron–Beryllium Scattering: Recommended Cross Sections
Publisher: AIP Publishing
Date: 09-2018
DOI: 10.1063/1.5047139
Abstract: We report results from the application of the relativistic complex optical potential (ROP) method to electron–beryllium scattering. The energy range of this study was 0–5000 eV, with the results for the integral elastic cross sections, momentum transfer cross sections, summed discrete electronic-state excitation integral cross sections, and total ionisation cross sections (TICSs) being reported. However we will largely focus our discussion here on the TICS, due to its importance in simulating the plasma action on beryllium (Be) in the international thermonuclear reactor. The current level of agreement between the various theoretical approaches to calculating the TICS is well summarised in the work of Maihom et al. [Eur. Phys. J. D 67, 2 (2013)] and Blanco et al. [Plasma Sources Sci. Technol. 26, 085004 (2017)], with the level of accord between them being quite marginal. As a consequence, we revisit this problem with improved scattering potentials over those employed in the work of Blanco et al. In addition, we present results from an application of the binary-encounter-Bethe theory for the electron–Be TICS. We find a quite significant improvement in the level of agreement between the TICS from our new ROP calculation and the earlier B-spline R-matrix and convergent close coupling results [O. Zatsarinny et al., J. Phys. B: At., Mol. Opt. Phys. 49, 235701 (2016)], compared to that reported in the work of Blanco et al. As a result of this improved level of accord, we propose here a recommended TICS for e+Be scattering, as well as for the elastic integral and summed electronic-state excitation cross sections, which also incorporates uncertainty estimates for their validity.
Electron impact ionization of 1-propanol
Publisher: Elsevier BV
Date: 11-2017
Electron impact ionization of 1-butanol: II. Total ionization cross sections and appearance energies
Publisher: Elsevier BV
Date: 07-2018
Positron transport in water vapour
Publisher: IOP Publishing
Date: 02-03-2012
Elastic cross sections for electron scattering from iodomethane
Publisher: IOP Publishing
Date: 02-2011
Electron impact ionization of R-carvone: I. Mass spectra and appearance energies
Publisher: Elsevier BV
Date: 10-2020
Regularities in positronium formation for atoms and molecules
Publisher: IOP Publishing
Date: 23-02-2016
DOI: 10.1088/0953-4075/49/6/064003
Abstract: In an effort to aid the modelling of positron and positronium (Ps) transport in biological media we have compiled recent experimental results for the total Ps formation in positron scattering from atoms and molecules. A simple function was found to adequately describe the total Ps formation cross section for both atoms and molecules. The parameters of this function describe the magnitude and shape of the Ps formation cross section and are compared to physical characteristics of the target atoms and molecules. A general trend in the magnitude of the total Ps formation cross section is observed as a function of the target atom/molecule dipole polarisability. The functional form may enable quick estimation of the Ps cross section for molecules for which experimental measurements or theoretical estimates do not exist.
Experimental and theoretical analysis for total electron scattering cross sections of benzene
Publisher: AIP Publishing
Date: 28-08-2019
DOI: 10.1063/1.5116076
Abstract: Measurements of the total electron scattering cross sections (TCSs) from benzene, in the impact energy range of 1–1000 eV, are presented here by combining two different experimental systems. The first utilizes a magnetically confined electron transmission beam for the lower energies (1–300 eV), while the second utilizes a linear transmission beam apparatus for the higher energies (100–1000 eV). These cross sections have also been calculated by means of two different theoretical methods, the Schwinger Multichannel with Pseudo Potential (SMCPP) procedure, employing two different approaches to account for the polarization of the target for impact energies between 0.1 and 15 eV, and the Independent Atom Model with the Screening Corrected Additivity Rule including Interference effect (IAM-SCAR+I) paradigm to cover the 10–10 000 eV impact energy range. The present results are compared with available theoretical and experimental data, with the level of accord being good in some cases and less satisfactory in others, and some predicted resonances have been identified. In particular, we found a π* shape resonance at 1.4 eV and another feature in the energy region 4.6–4.9 eV interpreted as a π* resonance (2B2g symmetry), which is a mixture of shape and a core excited resonance, as well as a Feshbach resonance at 5.87 eV associated with the 3s (a1g) Rydberg state. A Born-type formula to extrapolate TCS values for energies above 10 000 eV is also given. This study provides a complete set of TCS data, with uncertainty limits within 10%, ready to be used for modeling electron transport applications.
Integral elastic, vibrational-excitation, electronic-state excitation, ionization, and total cross sections for electron scattering from para-benzoquinone
Publisher: AIP Publishing
Date: 28-05-2018
DOI: 10.1063/1.5028298
Abstract: We report absolute experimental integral cross sections (ICSs) for the electron impact excitation of 6 bands (Bands 0-V) of unresolved electronic-states in para-benzoquinone, for incident electron energies between 20 and 40 eV. Absolute vibrational-excitation ICSs, for 3 composite vibrational bands (Bands I-III), are also reported in that same energy range. In addition, ICSs calculated within our independent atom model (IAM) with screening corrected additivity rule (SCAR) formalism, extended to account for interference (I) terms that arise due to the multi-centre nature of the scattering problem, are also reported. The sum of those ICSs gives the IAM-SCAR+I total cross section (TCS) for electron–para-benzoquinone scattering. Where possible, those calculated IAM-SCAR+I ICSs are compared against corresponding results from the present measurements with an acceptable level of accord being obtained. Similarly, we also present results from our Schwinger multichannel method with pseudopotential (SMCPP) calculations. Here elastic ICSs and ICSs corresponding to the Bands 0–III of unresolved electronic-states are presented, with agreement between the SMCPP electronic-state ICSs and those from our measurements being in good qualitative accord. The energy range of our SMCPP computations is 16–50 eV. Using the binary-encounter-Bethe (BEB) approach, total ionization cross sections for this collision system were computed. Those total ionization cross sections were then added to our SMCPP ICS results, to derive SMCPP/BEB TCSs that are typically in very good accord with those from our IAM-SCAR+I approach.
Chemistry induced during the thermalization and transport of positrons and secondary electrons in gases and liquids
Publisher: IOP Publishing
Date: 02-03-2015
Intermediate-energy differential and integral cross sections for vibrational excitation in α-tetrahydrofurfuryl alcohol
Publisher: AIP Publishing
Date: 03-06-2014
DOI: 10.1063/1.4879779
Abstract: Differential and integral cross section measurements, for incident electron energies in the 20–50 eV range, are reported for excitation of several composite vibrational modes in α-tetrahydrofurfuryl alcohol (THFA). Optimisation and frequency calculations, using GAUSSIAN 09 at the B3LYP/aug-cc-pVDZ level, were also undertaken for the two most abundant conformers of THFA, with results being reported for their respective mode classifications and excitation energies. Those calculations assisted us in the experimental assignments of the composite features observed in our measured energy loss spectra. There are, to the best of our knowledge, no other experimental or theoretical data currently available in the literature against which we can compare the present results.
Positron scattering from O2
Publisher: IOP Publishing
Date: 10-2012
Low Energy electron transport in furfural
Publisher: Springer Science and Business Media LLC
Date: 09-2017
Total electron-scattering cross sections from pyrimidine as measured using a magnetically confined experimental system
Publisher: American Physical Society (APS)
Date: 07-10-2013
Positron scattering from vinyl acetate
Publisher: IOP Publishing
Date: 21-08-2014
A dynamical (e,2e) investigation into the ionization of pyrazine
Publisher: Elsevier BV
Date: 10-2021
Positron Scattering from the Group IIB Metals Zinc and Cadmium: Recommended Cross Sections and Transport Simulations
Publisher: AIP Publishing
Date: 04-05-2021
DOI: 10.1063/5.0046091
Abstract: Results from the application of our optical potential and relativistic optical potential models to positron scattering from gas-phase zinc (Zn) and cadmium (Cd) are presented. In particular, integral cross sections (ICSs) for elastic scattering, positronium formation, summed discrete electronic-state excitation, and ionization scattering processes are reported for both species and over an extended incident positron energy range. From those ICSs, the total cross section is subsequently constructed by taking their sum. We note that there are currently no experimental data available for any of these scattering processes for either species, with earlier computational results being limited to the elastic channel and restricted to relatively narrow incident positron energy regimes. Nonetheless, we construct recommended positron cross section datasets for both zinc and cadmium over the incident positron energy range of 0–10 000 eV. The recommended positron cross section data are subsequently employed in a multi-term Boltzmann equation analysis to simulate the transport of positrons, under the influence of an applied (external) electric field, through the background Zn and Cd gases. Qualitatively similar behavior in the calculated transport coefficients was observed between both species. Finally, for the case of zinc, the present positron transport coefficients are compared against corresponding results from electron transport with some significant differences now being observed.
Total cross-sections for positron and electron scattering from α-tetrahydrofurfuryl alcohol
Publisher: IOP Publishing
Date: 10-06-2011
Kinetic Phenomena in Transport of Electrons and Positrons in Gases caused by the Properties of Scattering Cross Sections
Publisher: IOP Publishing
Date: 10-04-2014
Total electron scattering cross sections for pyrimidine and pyrazine as measured using a magnetically confined experimental system
Publisher: IOP Publishing
Date: 10-04-2014
Integral Cross Sections for Electron–Zinc Scattering over a Broad Energy Range (0.01–5000 eV)
Publisher: AIP Publishing
Date: 30-01-2020
DOI: 10.1063/1.5135573
Abstract: We report results from the application of our optical potential and relativistic optical potential methods to electron–zinc scattering. The energy range of this study was 0.01–5000 eV, with original results for the summed discrete electronic-state integral excitation cross sections and total ionization cross sections being presented here. When combined with our earlier elastic scattering data [Marinković et al., Phys. Rev. A 99, 062702 (2019)], and the quite limited experimental and theoretical results for those processes from other groups, we critically assemble a recommended integral cross section database for electron–zinc scattering. Electron transport coefficients are subsequently calculated for reduced electric fields ranging from 0.1 to 1000 Td, using a multiterm solution of Boltzmann’s equation. Some differences with corresponding results from the earlier study of White et al. [J. Phys. D: Appl. Phys. 37, 3185 (2004)] were noted, indicating in part the necessity of having accurate and complete cross section data, over a wide energy regime, when undertaking such transport simulations.
Total cross sections for electron scattering by 1-propanol at impact energies in the range 40-500 eV
Publisher: AIP Publishing
Date: 21-11-2017
DOI: 10.1063/1.5008621
Abstract: Absolute total cross section (TCS) measurements for electron scattering from 1-propanol molecules are reported for impact energies from 40 to 500 eV. These measurements were obtained using a new apparatus developed at Juiz de Fora Federal University—Brazil, which is based on the measurement of the attenuation of a collimated electron beam through a gas cell containing the molecules to be studied at a given pressure. Besides these experimental measurements, we have also calculated TCS using the Independent-Atom Model with Screening Corrected Additivity Rule and Interference (IAM-SCAR+I) approach with the level of agreement between them being typically found to be very good.
Differential cross sections for electron impact excitation of the electronic bands of phenol
Publisher: AIP Publishing
Date: 10-03-2015
DOI: 10.1063/1.4913825
Abstract: We report results from a joint theoretical and experimental investigation into electron scattering from the important organic species phenol (C6H5OH). Specifically, differential cross sections (DCSs) have been measured and calculated for the electron-impact excitation of the electronic states of C6H5OH. The measurements were carried out at energies in the range 15–40 eV, and for scattered-electron angles between 10∘ and 90∘. The energy resolution of those experiments was typically ∼80 meV. Corresponding Schwinger multichannel method with pseudo-potentials calculations, with and without Born-closure, were also performed for a sub-set of the excited electronic-states that were accessed in the measurements. Those calculations were conducted at the static exchange plus polarisation (SEP)-level using a minimum orbital basis for single configuration interaction (MOBSCI) approach. Agreement between the measured and calculated DCSs was typically fair, although to obtain quantitative accord, the theory would need to incorporate even more channels into the MOBSCI.
Electron collisions with phenol: Total, integral, differential, and momentum transfer cross sections and the role of multichannel coupling effects on the elastic channel
Publisher: AIP Publishing
Date: 10-03-2015
DOI: 10.1063/1.4913824
Abstract: We report theoretical and experimental total cross sections for electron scattering by phenol (C6H5OH). The experimental data were obtained with an apparatus based in Madrid and the calculated cross sections with two different methodologies, the independent atom method with screening corrected additivity rule (IAM-SCAR), and the Schwinger multichannel method with pseudopotentials (SMCPP). The SMCPP method in the Nopen-channel coupling scheme, at the static-exchange-plus-polarization approximation, is employed to calculate the scattering litudes at impact energies ranging from 5.0 eV to 50 eV. We discuss the multichannel coupling effects in the calculated cross sections, in particular how the number of excited states included in the open-channel space impacts upon the convergence of the elastic cross sections at higher collision energies. The IAM-SCAR approach was also used to obtain the elastic differential cross sections (DCSs) and for correcting the experimental total cross sections for the so-called forward angle scattering effect. We found a very good agreement between our SMCPP theoretical differential, integral, and momentum transfer cross sections and experimental data for benzene (a molecule differing from phenol by replacing a hydrogen atom in benzene with a hydroxyl group). Although some discrepancies were found for lower energies, the agreement between the SMCPP data and the DCSs obtained with the IAM-SCAR method improves, as expected, as the impact energy increases. We also have a good agreement among the present SMCPP calculated total cross section (which includes elastic, 32 inelastic electronic excitation processes and ionization contributions, the latter estimated with the binary-encounter-Bethe model), the IAM-SCAR total cross section, and the experimental data when the latter is corrected for the forward angle scattering effect [Fuss et al., Phys. Rev. A 88, 042702 (2013)].
Electron-impact excitation of the (
5 s 2 5
Publisher:
American Physical Society (APS)
Date:
03-08-2020
Publisher: American Physical Society (APS)
Date: 03-08-2020
Single electron tracks in water vapour for energies below 100 eV
Publisher: Elsevier BV
Date: 11-2008
Low energy lepton scattering: recent results for electron and positron interactions
Publisher: IOP Publishing
Date: 10-2008
The role of pyrimidine and water as underlying molecular constituents for describing radiation damage in living tissue: A comparative study
Publisher: AIP Publishing
Date: 06-2015
DOI: 10.1063/1.4921810
Abstract: Water is often used as the medium for characterizing the effects of radiation on living tissue. However, in this study, charged-particle track simulations are employed to quantify the induced physicochemical and potential biological implications when a primary ionising particle with energy 10 keV strikes a medium made up entirely of water or pyrimidine. Note that pyrimidine was chosen as the DNA/RNA bases cytosine, thymine, and uracil can be considered pyrimidine derivatives. This study aims to assess the influence of the choice of medium on the charged-particle transport, and identify how appropriate it is to use water as the default medium to describe the effects of ionising radiation on living tissue. Based on the respective electron interaction cross sections, we provide a model, which allows the study of radiation effects not only in terms of energy deposition (absorbed dose and stopping power) but also in terms of the number of induced molecular processes. Results of these parameters for water and pyrimidine are presented and compared.
Cross-section calculations for positron scattering from pyrimidine over an energy range from 0.1 to 10000 eV
Publisher: American Physical Society (APS)
Date: 04-12-2013
Investigating the role of vibrational excitation in simulating charged-particle tracks in liquid pyrimidine
Publisher: Springer Science and Business Media LLC
Date: 03-2016
Low-energy elastic electron interactions with pyrimidine
Publisher: American Physical Society (APS)
Date: 02-12-2011
A Complete Cross Section Data Set for Electron Scattering by Pyridine: Modelling Electron Transport in the Energy Range 0–100 eV
Publisher: MDPI AG
Date: 22-09-2020
DOI: 10.3390/IJMS21186947
Abstract: Electron scattering cross sections for pyridine in the energy range 0–100 eV, which we previously measured or calculated, have been critically compiled and complemented here with new measurements of electron energy loss spectra and double differential ionization cross sections. Experimental techniques employed in this study include a linear transmission apparatus and a reaction microscope system. To fulfill the transport model requirements, theoretical data have been recalculated within our independent atom model with screening corrected additivity rule and interference effects (IAM-SCAR) method for energies above 10 eV. In addition, results from the R-matrix and Schwinger multichannel with pseudopotential methods, for energies below 15 eV and 20 eV, respectively, are presented here. The reliability of this complete data set has been evaluated by comparing the simulated energy distribution of electrons transmitted through pyridine, with that observed in an electron-gas transmission experiment under magnetic confinement conditions. In addition, our representation of the angular distribution of the inelastically scattered electrons is discussed on the basis of the present double differential cross section experimental results.
Differential cross sections for low-energy elastic electron scattering from the CF3 radical
Publisher: IOP Publishing
Date: 04-12-2013
Total, elastic, and inelastic cross sections for positron and electron collisions with tetrahydrofuran
Publisher: AIP Publishing
Date: 15-02-2013
DOI: 10.1063/1.4789584
Abstract: We present total, elastic, and inelastic cross sections for positron and electron scattering from tetrahydrofuran (THF) in the energy range between 1 and 5000 eV. Total cross sections (TCS), positronium formation cross sections, the summed inelastic integral cross sections (ICS) for electronic excitations and direct ionization, as well as elastic differential cross sections (DCS) at selected incident energies, have been measured for positron collisions with THF. The positron beam used to carry out these experiments had an energy resolution in the range 40–100 meV (full-width at half-maximum). We also present TCS results for positron and electron scattering from THF computed within the independent atom model using the screening corrected additivity rule approach. In addition, we calculated positron-impact elastic DCS and the sum over all inelastic ICS (except rotations and vibrations). While our integral and differential positron cross sections are the first of their kind, we compare our TCS with previous literature values for this species. We also provide a comparison between positron and electron-impact cross sections, in order to uncover any differences or similarities in the scattering dynamics with these two different projectiles.
Positron Scattering from Gas-Phase Beryllium and Magnesium: Theory, Recommended Cross Sections, and Transport Simulations
Publisher: AIP Publishing
Date: 24-07-2019
DOI: 10.1063/1.5115353
Abstract: Results from the application of our optical potential and relativistic optical potential models to positron scattering from gas-phase beryllium (Be) and magnesium (Mg) are presented. Specifically, total cross sections and integral cross sections for the elastic, positronium formation, summed discrete electronic-state excitation, and ionization scattering processes are reported for both species and over an extended incident positron energy range. Where possible, these results are compared against the existing theoretical and experimental data, although it must be noted here that no current measurements are yet available for Be and those that are available for Mg are largely restricted to the total cross section. Nonetheless, on the basis of that comparison, recommended cross section datasets, for all the aforementioned cross sections, are formed. Those recommended cross section data are subsequently employed in a Boltzmann equation analysis to simulate the transport of positrons, under the influence of an applied (external) electric field, through the background Be and Mg gases. Note that relativistic optical potential results for the elastic momentum transfer cross section are also reported, to allow us to account for anisotropy effects in our transport simulations. Finally, our positron simulation results for quantities such as the ionization rate coefficients and flux and bulk drift velocities are compared with the corresponding electron transport results with significant differences being observed.
Electron interactions with tetrahydrofuran
Publisher: IOP Publishing
Date: 02-07-2012
Electron scattering cross sections from nitrobenzene in the energy range 0.4–1000 eV: the role of dipole interactions in measurements and calculations
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0CP02039G
Abstract: Absolute total electron scattering cross sections (TCS) for nitrobenzene molecules with impact energies from 0.4 to 1000 eV have been measured by means of two different electron-transmission experimental arrangements.
Electron impact cross-sections for biomolecules - completeness and self-consistency via swarm analysis
Publisher: IOP Publishing
Date: 07-09-2015
Electron-collision cross sections for iodine
Publisher: American Physical Society (APS)
Date: 08-04-2011
Experimental and theoretical cross sections for positron scattering from the pentane isomers
Publisher: AIP Publishing
Date: 24-02-2016
DOI: 10.1063/1.4942472
Abstract: Isomerism is ubiquitous in chemistry, physics, and biology. In atomic and molecular physics, in particular, isomer effects are well known in electron-impact phenomena however, very little is known for positron collisions. Here we report on a set of experimental and theoretical cross sections for low-energy positron scattering from the three structural isomers of pentane: normal-pentane, isopentane, and neopentane. Total cross sections for positron scattering from normal-pentane and isopentane were measured at the University of Trento at incident energies between 0.1 and 50 eV. Calculations of the total cross sections, integral cross sections for elastic scattering, positronium formation, and electronic excitations plus direct ionization, as well as elastic differential cross sections were computed for all three isomers between 1 and 1000 eV using the independent atom model with screening corrected additivity rule. No definitive evidence of a significant isomer effect in positron scattering from the pentane isomers appears to be present.
Transport properties of electron swarms in tetrahydrofuran under the influence of an applied electric field
Publisher: American Physical Society (APS)
Date: 26-12-2013
Positron scattering from pyridine
Publisher: AIP Publishing
Date: 11-04-2018
DOI: 10.1063/1.5024246
Abstract: We present a range of cross section measurements for the low-energy scattering of positrons from pyridine, for incident positron energies of less than 20 eV, as well as the independent atom model with the screening corrected additivity rule including interference effects calculation, of positron scattering from pyridine, with dipole rotational excitations accounted for using the Born approximation. Comparisons are made between the experimental measurements and theoretical calculations. For the positronium formation cross section, we also compare with results from a recent empirical model. In general, quite good agreement is seen between the calculations and measurements although some discrepancies remain which may require further investigation. It is hoped that the present study will stimulate development of ab initio level theoretical methods to be applied to this important scattering system.
Excitation of vibrational quanta in furfural by intermediate-energy electrons
Publisher: AIP Publishing
Date: 08-12-2015
DOI: 10.1063/1.4936631
Abstract: We report cross sections for electron-impact excitation of vibrational quanta in furfural, at intermediate incident electron energies (20, 30, and 40 eV). The present differential cross sections are measured over the scattered electron angular range 10°–90°, with corresponding integral cross sections subsequently being determined. Furfural is a viable plant-derived alternative to petrochemicals, being produced via low-temperature plasma treatment of biomass. Current yields, however, need to be significantly improved, possibly through modelling, with the present cross sections being an important component of such simulations. To the best of our knowledge, there are no other cross sections for vibrational excitation of furfural available in the literature, so the present data are valuable for this important molecule.
Total cross sections for positron and electron scattering from pyrimidine
Publisher: IOP Publishing
Date: 19-10-2010
Modelling low energy electron interactions for biomedical uses of radiation
Publisher: IOP Publishing
Date: 11-2009
Advances in positron and electron scattering*
Publisher: Springer Science and Business Media LLC
Date: 10-2016
Low energy positron interactions with uracil-Total scattering, positronium formation, and differential elastic scattering cross sections
Publisher: AIP Publishing
Date: 18-07-2014
DOI: 10.1063/1.4887072
Abstract: Measurements of the grand total and total positronium formation cross sections for positron scattering from uracil have been performed for energies between 1 and 180 eV, using a trap-based beam apparatus. Angular, quasi-elastic differential cross section measurements at 1, 3, 5, 10, and 20 eV are also presented and discussed. These measurements are compared to existing experimental results and theoretical calculations, including our own calculations using a variant of the independent atom approach.
An improved set of electron-THFA cross sections refined through a neural network-based analysis of swarm data
Publisher: AIP Publishing
Date: 24-02-2021
DOI: 10.1063/5.0043759
Abstract: We review experimental and theoretical cross sections for electron transport in α-tetrahydrofurfuryl alcohol (THFA) and, in doing so, propose a plausible complete set. To assess the accuracy and self-consistency of our proposed set, we use the pulsed-Townsend technique to measure drift velocities, longitudinal diffusion coefficients, and effective Townsend first ionization coefficients for electron swarms in admixtures of THFA in argon, across a range of density-reduced electric fields from 1 to 450 Td. These measurements are then compared to simulated values derived from our proposed set using a multi-term solution of Boltzmann’s equation. We observe discrepancies between the simulation and experiment, which we attempt to address by employing a neural network model that is trained to solve the inverse swarm problem of unfolding the cross sections underpinning our experimental swarm measurements. What results from our neural network-based analysis is a refined set of electron-THFA cross sections, which we confirm is of higher consistency with our swarm measurements than that which we initially proposed. We also use our database to calculate electron transport coefficients in pure THFA across a range of reduced electric fields from 0.001 to 10 000 Td.
Low-energy electron scattering from α-tetrahydrofurfuryl alcohol
Publisher: IOP Publishing
Date: 10-04-2014
Joint theoretical and experimental study on elastic electron scattering from bismuth
Publisher: American Physical Society (APS)
Date: 23-03-2020
Integral elastic, electronic-state, ionization, and total cross sections for electron scattering with furfural
Publisher: AIP Publishing
Date: 08-04-2016
DOI: 10.1063/1.4945562
Abstract: We report absolute experimental integral cross sections (ICSs) for electron impact excitation of bands of electronic-states in furfural, for incident electron energies in the range 20–250 eV. Wherever possible, those results are compared to corresponding excitation cross sections in the structurally similar species furan, as previously reported by da Costa et al. [Phys. Rev. A 85, 062706 (2012)] and Regeta and Allan [Phys. Rev. A 91, 012707 (2015)]. Generally, very good agreement is found. In addition, ICSs calculated with our independent atom model (IAM) with screening corrected additivity rule (SCAR) formalism, extended to account for interference (I) terms that arise due to the multi-centre nature of the scattering problem, are also reported. The sum of those ICSs gives the IAM-SCAR+I total cross section for electron–furfural scattering. Where possible, those calculated IAM-SCAR+I ICS results are compared against corresponding results from the present measurements with an acceptable level of accord being obtained. Similarly, but only for the band I and band II excited electronic states, we also present results from our Schwinger multichannel method with pseudopotentials calculations. Those results are found to be in good qualitative accord with the present experimental ICSs. Finally, with a view to assembling a complete cross section data base for furfural, some binary-encounter-Bethe-level total ionization cross sections for this collision system are presented.
Experimental and theoretical cross sections for elastic electron scattering from zinc
Publisher: American Physical Society (APS)
Date: 10-06-2019
Modelling low energy electron and positron tracks for biomedical applications
Publisher: Informa UK Limited
Date: 16-09-2012
DOI: 10.3109/09553002.2011.624151
Abstract: To incorporate the effects of low energy electrons and positrons into radiation interaction models. The simulation method proposed here was based on experimental and theoretical cross section data and energy loss spectra we have previously derived. After a summary of the main techniques used to obtain reliable input data, the basis of a Low Energy Particle Track Simulation (LEPTS) procedure was established. The programme is specifically designed to describe electron and positron interactions below 10 keV, down to thermal energies. Single electron and positron tracks in water are presented and the possibility of using these results to develop tools for nanodosimetry is discussed. Standard approximations based on high incident energies, such as the Born-Bethe theory, are not suitable to simulate electron and positron tracks below 10 keV. Prior to the inclusion of low-energy effects in a radiation model, an appropriate study is required to determine both the interaction cross sections and the energy loss spectra.
Differential cross sections for intermediate-energy electron scattering from α-tetrahydrofurfuryl alcohol: Excitation of electronic-states
Publisher: AIP Publishing
Date: 08-07-2014
DOI: 10.1063/1.4885856
Abstract: We report on measurements of differential cross sections (DCSs) for electron impact excitation of a series of Rydberg electronic-states in α-tetrahydrofurfuryl alcohol (THFA). The energy range of these experiments was 20–50 eV, while the scattered electron was detected in the 10°–90° angular range. There are currently no other experimental data or theoretical computations against which we can directly compare the present measured results. Nonetheless, we are able to compare our THFA DCSs with earlier cross section measurements for Rydberg-state electronic excitation for tetrahydrofuran, a similar cyclic ether, from Do et al. [J. Chem. Phys. 134, 144302 (2011)]. In addition, “rotationally averaged” elastic DCSs, calculated using our independent atom model with screened additivity rule correction approach are also reported. Those latter results give integral cross sections consistent with the optical theorem, and supercede those from the only previous study of Milosavljević et al. [Eur. Phys. J. D 40, 107 (2006)].
Interaction model for electron scattering from ethylene in the energy range 1–10000eV
Publisher: Elsevier BV
Date: 02-2013
Monte Carlo Model of Positron Transport in Water: Track Structures Based on Atomic and Molecular Scattering Data for Positrons
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 11-2011
Recommended Cross Sections for Electron–Indium Scattering
Publisher: AIP Publishing
Date: 29-01-2021
DOI: 10.1063/5.0035218
Abstract: We report, over an extended energy range, recommended angle-integrated cross sections for elastic scattering, discrete inelastic scattering processes, and the total ionization cross section for electron scattering from atomic indium. In addition, from those angle-integrated cross sections, a grand total cross section is subsequently derived. To construct those recommended cross-section databases, results from original B-spline R-matrix, relativistic convergent close-coupling, and relativistic optical-potential computations are also presented here. Electron transport coefficients are subsequently calculated, using our recommended database, for reduced electric fields ranging from 0.01 Td to 10 000 Td using a multiterm solution of Boltzmann’s equation. To facilitate those simulations, a recommended elastic momentum transfer cross-section set is also constructed and presented here.
Integral Cross Sections for Electron–Magnesium Scattering Over a Broad Energy Range (0–5000 eV)
Publisher: AIP Publishing
Date: 12-2018
DOI: 10.1063/1.5081132
Abstract: We report the results from the application of our optical potential and relativistic optical potential (ROP) methods to electron–magnesium scattering. The energy range of this study was 0–5000 eV, with the results for the integral elastic cross sections, summed discrete electronic-state excitation integral cross sections, momentum transfer cross sections, and total ionisation cross sections being reported. Where possible, we compare the present results to the available experimental data and to the earlier results from close coupling and R-matrix type computations. Typically, a quite fair level of accord is found between our ROP calculations and the earlier theoretical and experimental cross sections. Additionally, from the assembled database, we provide for the modeling community some recommended cross section sets for use in their simulations, in which magnesium is a constituent. Electron transport coefficients are subsequently calculated for reduced electric fields ranging from 0.1 to 1000 Td using a multi-term solution of Boltzmann’s equation. Substantial differences in the transport coefficients between the ROP calculations and the recommended cross sections are observed over the range of fields considered, clearly illustrating the importance of the veracity of the database in the simulations.
Interaction of photoionisation and meteoric input in the atmosphere of Jupiter
Publisher: Springer Science and Business Media LLC
Date: 12-2019
Electron-scattering cross sections for collisions with tetrahydrofuran from 50 to 5000 eV
Publisher: American Physical Society (APS)
Date: 19-11-2009
Experimental and theoretical cross sections for positron collisions with 3-hydroxy-tetrahydrofuran
Publisher: AIP Publishing
Date: 15-02-2013
DOI: 10.1063/1.4790620
Abstract: Cross section results from a joint experimental and theoretical investigation into positron scattering from 3-hydroxy-tetrahydrofuran (3H-THF) are presented. Total and positronium (Ps) formation cross sections have been measured from 1 to 190 eV using the positron beamline at the Australian National University, which has an energy resolution between 60 and 100 meV. The total cross section (TCS) and the elastic and total inelastic integral cross sections in the energy range between 1 and 1000 eV have been computed within the Independent Atom Model using the Screening Corrected Additivity Rule approach. In addition, we have calculated elastic differential cross sections at selected incident energies. Our computations represent the first theoretical results reported for this target species, while our measured Ps formation cross sections are also novel. Comparison of the present TCS with the previous results from the University of Trento shows a good level of agreement at the lowest energies. We also provide a comparison between the present cross sections for 3H-THF and those from our earlier study on the parent molecule tetrahydrofuran.
Elastic scattering and vibrational excitation for electron impact on para-benzoquinone
Publisher: AIP Publishing
Date: 28-12-2017
DOI: 10.1063/1.5010831
Abstract: We report on theoretical elastic and experimental vibrational-excitation differential cross sections (DCSs) for electron scattering from para-benzoquinone (C6H4O2), in the intermediate energy range 15–50 eV. The calculations were conducted with two different theoretical methodologies, the Schwinger multichannel method with pseudopotentials (SMCPP) and the independent atom method with screening corrected additivity rule (IAM-SCAR) that also now incorporates a further interference (I) term. The SMCPP with N energetically open electronic states (Nopen) at the static-exchange-plus-polarisation (Nopench-SEP) level was used to calculate the scattering litudes using a channel coupling scheme that ranges from 1ch-SE up to the 89ch-SEP level of approximation. We found that in going from the 38ch-SEP to the 89ch-SEP, at all energies considered here, the elastic DCSs did not change significantly in terms of both their shapes and magnitudes. This is a good indication that our SMCPP 89ch-SEP elastic DCSs are converged with respect to the multichannel coupling effect for the investigated intermediate energies. While agreement between our IAM-SCAR+I and SMCPP 89ch-SEP computations improves as the incident electron energy increases from 15 eV, overall the level of accord is only marginal. This is particularly true at middle scattering angles, suggesting that our SCAR and interference corrections are failing somewhat for this molecule below 50 eV. We also report experimental DCS results, using a crossed-beam apparatus, for excitation of some of the unresolved (“hybrid”) vibrational quanta (bands I–III) of para-benzoquinone. Those data were derived from electron energy loss spectra that were measured over a scattered electron angular range of 10°–90° and put on an absolute scale using our elastic SMCPP 89ch-SEP DCS results. The energy resolution of our measurements was ∼80 meV, which is why, at least in part, the observed vibrational features were only partially resolved. To the best of our knowledge, there are no other experimental or theoretical vibrational excitation results against which we might compare the present measurements.
On the use of Monte Carlo simulations to model transport of positrons in gases and liquids
Publisher: Elsevier BV
Date: 2014
DOI: 10.1016/J.APRADISO.2013.01.010
Abstract: In this paper we make a parallel between the swarm method in physics of ionized gases and modeling of positrons in radiation therapy and diagnostics. The basic idea is to take advantage of the experience gained in the past with electron swarms and to use it in establishing procedures of modeling positron diagnostics and therapy based on the well-established experimental binary collision data. In doing so we discuss the application of Monte Carlo technique for positrons in the same manner as used previously for electron swarms, we discuss the role of complete cross section sets (complete in terms of number, momentum and energy balance and tested against measured swarm parameters), we discuss the role of benchmarks and how to choose benchmarks for electrons that may perhaps be a subject to experimental verification. Finally we show some s les of positron trajectories together with secondary electrons that were established solely on the basis of accurate binary cross sections and also how those may be used in modeling of both gas filled traps and living organisms.
Total electron scattering cross sections from para-benzoquinone in the energy range 1–200 eV
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8CP03297A
Abstract: Total electron scattering cross sections, from para -benzoquinone, for impact energies ranging between 1 to 200 eV, have been obtained by measuring the attenuation of a linear electron beam under magnetic confinement conditions.
Cross Sections for Electron Scattering from Cadmium: Theory and Experiment
Publisher: AIP Publishing
Date: 16-05-2023
DOI: 10.1063/5.0145933
Abstract: Results from the application of optical potential, relativistic optical potential, relativistic convergent close-coupling, and binary encounter Bethe models to electron scattering from gas-phase cadmium are presented. In particular, integral cross sections for elastic scattering, summed discrete electronic-state excitation, and ionization scattering processes are reported over an extended incident electron-energy range. Total cross sections are constructed by taking their sum. Measurements are presented for elastic scattering and for excitation to the 51P1 state. The theoretical and experimental results are compared to previous calculations and measurements. Recommended electron cross-section datasets are constructed over an incident electron energy range of 0.01–10 000 eV.
Electron scattering from 1-butanol at intermediate impact energies: Total cross sections
Publisher: AIP Publishing
Date: 20-05-2019
DOI: 10.1063/1.5096211
Abstract: We report experimental measurements of the absolute total cross sections (TCSs) for electron scattering from 1-butanol at impact energies in the range 80–400 eV. Those measurements were conducted by considering the attenuation of a collimated electron beam, at a given energy, through a gas cell containing 1-butanol, at a given pressure, and through application of the Beer-Lambert law to derive the required TCS. We also report theoretical results using the Independent-Atom Model with Screening Corrected Additivity Rule and Interference approach. Those results include the TCS, the elastic integral cross section (ICS), the ionization total ICS, and the sum over all excitation process ICSs with agreement at the TCS level between our measured and calculated results being encouraging.
Total cross section of furfural by electron impact: Experiment and theory
Publisher: AIP Publishing
Date: 08-2017
DOI: 10.1063/1.4996462
Abstract: We present experimental total cross sections for electron scattering from furfural in the energy range from 10 to 1000 eV, as measured using a double electrostatic analyzer gas cell electron transmission experiment. These results are compared to theoretical data for furfural, as well as to experimental and theoretical values for the structurally similar molecules furan and tetrahydrofuran. The measured total cross section is in agreement with the theoretical results obtained by means of the independent-atom model with screening corrected additivity rule including interference method. In the region of higher electron energies, from 500 eV to 10 keV, the total electron scattering cross section is also estimated using a semi-empirical model based on the number of electrons and dipole polarizabilities of the molecular targets. Together with the recently measured differential and integral cross sections, and the furfural energy-loss spectra, the present total cross section data nearly complete the data set that is required for numerical simulation of low-energy electron processes in furfural, covering the range of projectile energies from a few electron volts up to 10 keV.
Positron scattering from pyrazine
Publisher: American Physical Society (APS)
Date: 12-10-2021
Current prospects on Low Energy Particle Track Simulation for biomedical applications
Publisher: Elsevier BV
Date: 2014
DOI: 10.1016/J.APRADISO.2013.01.017
Abstract: The Low Energy Particle Track Simulation code is a radiation interaction simulation tool specifically designed to describe electron and positron interactions below 10 keV at a molecular level. Relying on carefully selected, preferentially experimental input parameters that account for all expected scattering processes, it provides detailed results about all collisional events undergone by an incident radiation particle during its slowdown until thermalisation. Here, we give an up-to-date description of its input data sources and selection procedure and summarise the current contents of the resulting database.
A joint theoretical and experimental study for elastic electron scattering from 1,4-dioxane
Publisher: AIP Publishing
Date: 02-07-2013
DOI: 10.1063/1.4812215
Abstract: We present results of measurements and calculations of elastic electron scattering from 1,4-dioxane in the energy range of 0–1000 eV. Absolute differential and integral elastic cross sections have been measured using a crossed electron-molecule beam spectrometer and the relative flow technique, at four energies in the 10–30 eV range and for scattered electrons in the angular range 20°–129°. The measured cross sections are compared with results from R-matrix computations, at the static exchange plus polarization level, calculated at energies between 0–20 eV, and with calculations employing the independent atom model with the screening corrected additivity rule (IAM-SCAR). Those latter computations were conducted at energies between 1 and 1000 eV. Agreement between the measured and R-matrix cross sections was typically found to be good at all common energies, whereas agreement with IAM-SCAR was satisfactory only at 30 eV. To the best of our knowledge, the present results are the first absolute data to be published in the literature for this scattering system.
Electron-impact electronic-state excitation of para-benzoquinone
Publisher: AIP Publishing
Date: 27-03-2018
DOI: 10.1063/1.5023494
Abstract: Angle resolved electron energy loss spectra (EELS) for para-benzoquinone (C6H4O2) have been recorded for incident electron energies of 20, 30, and 40 eV. Measured differential cross sections (DCSs) for electronic band features, composed of a combination of energetically unresolved electronic states, are subsequently derived from those EELS. Where possible, the obtained DCSs are compared with those calculated using the Schwinger multichannel method with pseudopotentials. These calculations were performed using a minimum orbital basis single configuration interaction framework at the static exchange plus polarisation level. Here, quite reasonable agreement between the experimental cross sections and the theoretical cross sections for the summation of unresolved states was observed.
Anomalously large low-energy elastic cross sections for electron scattering from the CF3 radical
Publisher: Elsevier BV
Date: 05-2013
Self-consistent electron–THF cross sections derived using data-driven swarm analysis with a neural network model
Publisher: IOP Publishing
Date: 07-11-2020
Cross sections for positron and electron collisions with an analog of the purine nucleobases: Indole
Publisher: American Physical Society (APS)
Date: 26-01-2015
Electron impact ionization and fragmentation of biofuels
Publisher: Springer Science and Business Media LLC
Date: 05-2020
Electron and Positron Scattering Cross Sections from CO2: A Comparative Study over a Broad Energy Range (0.1–5000 eV)
Publisher: American Chemical Society (ACS)
Date: 07-09-2022
Spatial profiles of positrons injected at low energies into water: influence of cross section models
Publisher: IOP Publishing
Date: 15-03-2017
Electron swarm transport in THF and water mixtures
Publisher: Springer Science and Business Media LLC
Date: 05-2014
Corrigendum: Modelling single positron tracks in Ar
Publisher: IOP Publishing
Date: 07-09-2012
Scattering data for modelling positron tracks in gaseous and liquid water
Publisher: IOP Publishing
Date: 15-06-2016
Low-energy electron and positron transport in gases and soft-condensed systems of biological relevance
Publisher: Elsevier BV
Date: 2014
DOI: 10.1016/J.APRADISO.2013.01.008
Abstract: We present a study of electron and positron transport in water in both the gaseous and liquid states using a Boltzmann equation analysis and a Monte-Carlo simulation technique. We assess the importance of coherent scattering processes when considering transport of electrons ositrons in dense gases and liquids. We highlight the importance of electron and positron swarm studies and experiments as a test of the accuracy and completeness of cross-sections, as well as a technique for benchmarking Monte-Carlo simulations. The thermalization of low-energy positrons (<150 eV) in water is discussed and the sensitivity of the profiles to the form of the cross-sections in this energy region, and assumptions in the microscopic processes, is considered.
Modelling low energy electron and positron tracks for biomedical applications
Publisher: IOP Publishing
Date: 05-11-2012
Theoretical and experimental differential cross sections for electron impact excitation of the electronic bands of furfural
Publisher: AIP Publishing
Date: 28-03-2016
DOI: 10.1063/1.4944615
Abstract: We report results from a joint experimental and theoretical investigation into electron scattering from the important industrial species furfural (C5H4O2). Specifically, differential cross sections (DCSs) have been measured and calculated for the electron-impact excitation of the electronic states of C5H4O2. The measurements were carried out at energies in the range 20–40 eV, and for scattered-electron angles between 10° and 90°. The energy resolution of those experiments was typically ∼80 meV. Corresponding Schwinger multichannel method with pseudo-potential calculations, for energies between 6–50 eV and with and without Born-closure, were also performed for a sub-set of the excited electronic-states that were accessed in the measurements. Those calculations were undertaken at the static exchange plus polarisation-level using a minimum orbital basis for single configuration interaction (MOB-SCI) approach. Agreement between the measured and calculated DCSs was qualitatively quite good, although to obtain quantitative accord, the theory would need to incorporate even more channels into the MOB-SCI. The role of multichannel coupling on the computed electronic-state DCSs is also explored in some detail.
Electron and Positron Scattering from Pyrimidine
Publisher: IOP Publishing
Date: 05-11-2012
The electron-furfural scattering dynamics for 63 energetically open electronic states
Publisher: AIP Publishing
Date: 28-03-2016
DOI: 10.1063/1.4944616
Abstract: We report on integral-, momentum transfer- and differential cross sections for elastic and electronically inelastic electron collisions with furfural (C5H4O2). The calculations were performed with two different theoretical methodologies, the Schwinger multichannel method with pseudopotentials (SMCPP) and the independent atom method with screening corrected additivity rule (IAM-SCAR) that now incorporates a further interference (I) term. The SMCPP with N energetically open electronic states (Nopen) at either the static-exchange (Nopen ch-SE) or the static-exchange-plus-polarisation (Nopen ch-SEP) approximation was employed to calculate the scattering litudes at impact energies lying between 5 eV and 50 eV, using a channel coupling scheme that ranges from the 1ch-SEP up to the 63ch-SE level of approximation depending on the energy considered. For elastic scattering, we found very good overall agreement at higher energies among our SMCPP cross sections, our IAM-SCAR+I cross sections and the experimental data for furan (a molecule that differs from furfural only by the substitution of a hydrogen atom in furan with an aldehyde functional group). This is a good indication that our elastic cross sections are converged with respect to the multichannel coupling effect for most of the investigated intermediate energies. However, although the present application represents the most sophisticated calculation performed with the SMCPP method thus far, the inelastic cross sections, even for the low lying energy states, are still not completely converged for intermediate and higher energies. We discuss possible reasons leading to this discrepancy and point out what further steps need to be undertaken in order to improve the agreement between the calculated and measured cross sections.
Electron scattering from tetrahydrofuran
Publisher: IOP Publishing
Date: 05-11-2012
An experimental and theoretical investigation into positron and electron scattering from formaldehyde
Publisher: IOP Publishing
Date: 02-09-2011
Absolute partial ionization cross sections for electron impact of R-carvone from threshold to 100 eV
Publisher: Springer Science and Business Media LLC
Date: 08-2021
Low-energy positron and electron scattering from nitrogen dioxide
Publisher: IOP Publishing
Date: 22-11-2013
Low-energy positron and electron scattering from tetrahydrofuran and 3-hydroxy-tetrahydrofuran
Publisher: IOP Publishing
Date: 10-04-2014
A complete data set for the simulation of electron transport through gaseous tetrahydrofuran in the energy range 1–100 $$\hbox {eV}$$
Publisher: Springer Science and Business Media LLC
Date: 12-2021
DOI: 10.1140/EPJD/S10053-021-00300-7
Abstract: A self-consistent data set, with all the necessary inputs for Monte Carlo simulations of electron transport through gaseous tetrahydrofuran (THF) in the energy range 1–100 eV, has been critically compiled in this study. Accurate measurements of total electron scattering cross sections (TCSs) from THF have been obtained, and considered as reference values to validate the self-consistency of the proposed data set. Monte Carlo simulations of the magnetically confined electron transport through a gas cell containing THF for different beam energies (3, 10 and 70 eV) and pressures (2.5 and 5.0 mTorr) have also been performed by using a novel code developed in Madrid. In order to probe the accuracy of the proposed data set, the simulated results have been compared with the corresponding experimental data, the latter obtained with the same experimental configuration where the TCSs have been measured.
Differential cross sections for the electron-impact near-threshold electronic excitation of argon
Publisher: IOP Publishing
Date: 11-2009
An investigation into electron scattering from pyrazine at intermediate and high energies
Publisher: AIP Publishing
Date: 14-11-2013
DOI: 10.1063/1.4829771
Abstract: Total electron scattering cross sections for pyrazine in the energy range 10–500 eV have been measured with a new magnetically confined electron transmission-beam apparatus. Theoretical differential and integral elastic, as well as integral inelastic, cross sections have been calculated by means of a screening-corrected form of the independent-atom representation (IAM-SCAR) from 10 to 1000 eV incident electron energies. The present experimental and theoretical total cross sections show a good level of agreement, to within 10%, in the overlapping energy range. Consistency of these results with previous calculations (i.e., the R-matrix and Schwinger Multichannel methods) and elastic scattering measurements at lower energies, below 10 eV, is also discussed.
Positron interactions with water–total elastic, total inelastic, and elastic differential cross section measurements
Publisher: AIP Publishing
Date: 28-01-2014
DOI: 10.1063/1.4862685
Abstract: Utilising a high-resolution, trap-based positron beam, we have measured both elastic and inelastic scattering of positrons from water vapour. The measurements comprise differential elastic, total elastic, and total inelastic (not including positronium formation) absolute cross sections. The energy range investigated is from 1 eV to 60 eV. Comparison with theory is made with both R-Matrix and distorted wave calculations, and with our own application of the Independent Atom Model for positron interactions.
Intermediate energy cross sections for electron-impact vibrational-excitation of pyrimidine
Publisher: AIP Publishing
Date: 04-09-2015
DOI: 10.1063/1.4929907
Abstract: We report differential cross sections (DCSs) and integral cross sections (ICSs) for electron-impact vibrational-excitation of pyrimidine, at incident electron energies in the range 15–50 eV. The scattered electron angular range for the DCS measurements was 15°–90°. The measurements at the DCS-level are the first to be reported for vibrational-excitation in pyrimidine via electron impact, while for the ICS we extend the results from the only previous condensed-phase study [P. L. Levesque, M. Michaud, and L. Sanche, J. Chem. Phys. 122, 094701 (2005)], for electron energies ⩽12 eV, to higher energies. Interestingly, the trend in the magnitude of the lower energy condensed-phase ICSs is much smaller when compared to the corresponding gas phase results. As there is no evidence for the existence of any shape-resonances, in the available pyrimidine total cross sections [Baek et al., Phys. Rev. A 88, 032702 (2013) Fuss et al., ibid. 88, 042702 (2013)], between 10 and 20 eV, this mismatch in absolute magnitude between the condensed-phase and gas-phase ICSs might be indicative for collective-behaviour effects in the condensed-phase results.
Near-threshold electron-impact excitation of argon studied with the time-of-flight technique
Publisher: Springer Science and Business Media LLC
Date: 12-2009
Mass spectra and appearance energies of cationic fragments for electron ionization of 2-butanol
Publisher: Springer Science and Business Media LLC
Date: 11-2022
Electron transport in biomolecular gaseous and liquid systems: theory, experiment and self-consistent cross-sections
Publisher: IOP Publishing
Date: 15-05-2018
Modelling single positron tracks in Ar
Publisher: IOP Publishing
Date: 07-02-2012
Recent progress in electron scattering from atoms and molecules
Publisher: AIP Publishing LLC
Date: 2014
DOI: 10.1063/1.4866925
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