ORCID Profile
0000-0001-5355-8030
Current Organisation
Deakin University
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Publisher: AIP Publishing
Date: 15-07-1992
DOI: 10.1063/1.463286
Abstract: A previous quasiclassical trajectory investigation of a generic proton-transfer reaction [Lim and Brauman, J. Chem. Phys. 94, 7164 (1991)] suggested the existence of both the usual centrifugal barrier transition state and a ‘‘dynamic’’ nonenergetic transition state for association on a barrierless potential surface. This paper reports a microcanonical variational transition state theory investigation of the same potential surface. The dynamic transition state is found to fulfill the variational criterion of a minimum in the sum of states. Implications for ion/molecule reactions are discussed.
Publisher: Elsevier BV
Date: 2004
Publisher: Elsevier BV
Date: 09-2007
Publisher: Royal Society of Chemistry (RSC)
Date: 1999
DOI: 10.1039/A900927B
Publisher: Wiley
Date: 2011
DOI: 10.1002/SIA.3510
Abstract: Imaging SIMS is used to investigate the recovery of erased serial numbers from polypropylene, polycarbonate and polyvinylchloride substrates. The recovery of the serial numbers is initiated by a swelling mechanism due to the application of two swelling agents: methyleugenol and cinnamaldehyde. The localization of the characteristic molecular ions for the swelling agents is observed in regions associated with erased characters. This study examines and evaluates SIMS images to discover the optimum combination of the polymer and solvents. The results are discussed in reference to the Hildebrand solubility parameter and comments upon the limitations of this suggested indicator. Copyright © 2010 John Wiley & Sons, Ltd.
Publisher: AIP Publishing
Date: 16-07-2012
DOI: 10.1063/1.4733287
Abstract: Calculated energy profiles for the reactions of neutral Nb2 and Nb3 metal clusters with CO, D2, N2, and O2 are presented. In each reaction path, both a physisorption energy minimum, where the reactant remains intact, and a chemisorption energy minimum, where the reactant has dissociated, are calculated and linked by saddle points. We calculate branching ratios for the forward (dissociative) and reverse reactions which we compare with the experimental kinetic data. It is found that a combination of average thermal energies and barrier heights leads to wide variation in branching ratios which compares favourably to previously determined experimental reaction rates.
Publisher: Wiley
Date: 03-2004
DOI: 10.1002/BIO.756
Abstract: This review concerns the use of hypochlorite, hypobromite and related oxidants (such as N-bromosuccinimide and 1,3-dibromo-5,5-dimethylhydantoin) as chemiluminescence reagents and includes references to 249 papers that were published prior to mid-2003. Particular emphasis has been placed on proposed emitting species and the mechanisms of the light-producing pathways. The analytical applications of this chemistry have been summarized in three tables: (1) quantification of hypohalites and related compounds (including halides, which are initially oxidized) (2) enhancement or inhibition of luminol chemiluminescence and (3) direct chemiluminescence reactions with hypohalite reagents.
Publisher: AIP Publishing
Date: 15-04-1992
DOI: 10.1063/1.462639
Abstract: Classical trajectory calculations of the rate of collisional energy transfer between a bath gas and a highly excited polyatomic method, and the average energy transferred per collision, as functions of the bath gas translational energy and temperature, are reported. The method used is that of Lim and Gilbert [J. Phys. Chem. 94, 72 (1990)], which requires only about 500 trajectories for convergence, and generates extensive data on the collisional energy transfer between Xe and azulene, as a function of temperature, initial relative translational energy (E′T), and azulene initial internal energy (E′). The observed behavior can be explained qualitatively in terms of the Xe interacting in a chattering collision with a few substrate atoms, with the collision duration being much too brief to permit ergodicity but with a general tendency to transfer energy from hotter to colder modes (both internal and translational). At thermal energies, trajectory and experimental data show that the root-mean-squared energy transfer per collision, 〈ΔE2〉1/2, is relatively less dependent on E′ than the mean energy transfer 〈ΔE〉. The calculated temperature dependence is weak: 〈ΔE2〉1/2∝T0.3, corresponding to 〈ΔEdown〉∝T0.23. Values for the calculated average rotational energy transferred per collision (data currently only available from trajectories, and required for falloff calculations for radical–radical and ion-molecule reactions) are of the order of kBT, and similar to those for the internal energy there is extensive collision-induced internal-rotational energy transfer. The biased random walk ‘‘model B,’’ as discussed in text, is found to be in accord with much of the trajectory data and with experiment. This suggests that energy transfer is through pseudorandom multiple interactions between the bath gas and a few reactant atoms the ‘‘kick’’ given by the force at the turning point of each atom–atom encounter governs the amount of energy transferred. Moreover, a highly simplified version of this model explains why average energies transferred per collision for simple bath gases have the order-of-magnitude values seen experimentally, an explanation which has not been provided hitherto.
Publisher: Royal Society of Chemistry (RSC)
Date: 2008
DOI: 10.1039/B808424F
Abstract: Lawsone (2-hydroxy-1,4-naphthoquinone) reacts with latent fingermark deposits on paper surfaces to yield purple-brown impressions of ridge details which are also photoluminescent this compound represents the first in a completely new class of fingermark detection reagents.
Publisher: AIP Publishing
Date: 08-07-1995
DOI: 10.1063/1.470096
Abstract: Quasiclassical trajectory calculations of the energy transfer of highly vibrationally excited benzene and hexafluorobenzene (HFB) molecules colliding with helium, argon and xenon have been performed. Deactivation is found to be more efficient for HFB in accord with experiment. This effect is due to the greater number of low frequency vibrational modes in HFB. A correlation between the energy transfer parameters and the properties of the intramolecular potential is found. For benzene and HFB, average energies transferred per collision in the given energy range increase with energy. Besides weak collisions, more efficient ‘‘supercollisions’’ are also observed for all substrate–bath gas pairs. The histograms for vibrational energy transfer can be fitted by biexponential transition probabilities. Rotational energy transfer reveals similar trends for benzene and HFB. Cooling of rotationally hot ensembles is very efficient for both molecules. During the deactivation, the initially thermal rotational distribution heats up more strongly for argon or xenon as a collider, than for helium, leading to a quasi-steady-state in rotational energy after only a few collisions.
Publisher: Royal Society of Chemistry (RSC)
Date: 2007
DOI: 10.1039/B702804K
Abstract: Indole has an acidic N-H that can be used to form hydrogen bonds to anions and in this paper the synthesis of three new suitably functionalised indole based anion receptors is presented along with their evaluation using (1)H NMR titration techniques.
Publisher: American Chemical Society (ACS)
Date: 1990
DOI: 10.1021/J100364A011
Publisher: IOP Publishing
Date: 25-07-2022
Abstract: The ability to interpret, select, use and construct appropriate diagrams is fundamental for the study of physics and other science, technology, engineering, and mathematics (STEM) disciplines. Despite the importance of using and constructing appropriate diagrams in STEM, the ability to incorporate freehand drawing, or similar capabilities, into online formative and summative assessment is largely unavailable to educators. This paper reports on a new compass clock face question type that can be easily implemented within the quiz feature of any learning management system. This question type has many features of a freehand drawing response for testing particular concepts. Online examination questions from a first-year undergraduate unit at the author’s home institution are presented as ex les.
Publisher: Elsevier BV
Date: 08-2008
DOI: 10.1016/J.ACA.2008.06.041
Abstract: Although potassium permanganate [Mn(VII)] has been used extensively as a chemiluminescence reagent for many decades, other manganese-based oxidants have only recently been explored for this purpose. There is strong evidence to suggest that, like permanganate, manganese(III) and manganese(IV) oxidants react with many molecules to produce an excited manganese(II) species that emits light. However, these reagents differ markedly in terms of selectivity, and possess characteristics that provide new avenues for detection, such as the immobilisation of solid manganese dioxide, the production of 'soluble' manganese(IV) nanoparticles, and the electrochemical generation of manganese(III). In this review we examine the emergence of these alternative manganese oxidants as chemiluminescence reagents.
Publisher: Royal Society of Chemistry (RSC)
Date: 1999
DOI: 10.1039/A808024K
Publisher: Elsevier BV
Date: 06-2002
Publisher: AIP Publishing
Date: 02-04-0005
DOI: 10.1063/1.466882
Abstract: Experimental studies of collisional energy transfer from highly vibrationally excited toluene to various bath gases have recently been reported [Toselli and Barker, J. Chem. Phys. 97, 1809 (1992), and references therein]. A quasiclassical trajectory investigation for toluene in argon bath gas at 300 K for initial internal energies E′=41 000, 30 000, and 15 000 cm−1 is reported here. Collisional energy transfer is almost linearly dependent on E′. Predictions of energy transfer quantities are very sensitive to the average well depth of the assumed in idual pairwise potentials, but is less sensitive to the detailed shape. Qualitative and quantitative agreement with experiment is obtained where the overall well depth is physically realistic. Isotope studies using 40Ar and pseudohelium (4Ar) bath gases indicate that energy transfer is independent of the mass of the bath-gas collider, but perdeuteration increases 〈ΔE2〉1/2 by 13% over the undeuterated values.
Publisher: American Chemical Society (ACS)
Date: 1990
DOI: 10.1021/J100364A012
Publisher: Society of Computer Chemistry Japan
Date: 2006
DOI: 10.2477/JCCJ.5.139
Publisher: Wiley
Date: 04-1987
Publisher: Elsevier BV
Date: 06-12-2002
DOI: 10.1016/S0039-9140(02)00426-5
Abstract: The increased demands placed on solution propulsion by programmed flow systems, such as sequential injection analysis, lab-on-value technology, bead injection and multi-commutation, has highlighted the inability of many conventional pumps to generate a smooth, consistent flow. A number of researchers have examined ways to overcome the inadvertent, uncontrolled pulsation caused by the mechanical aciton of peristaltic pumps. In contrast, we have developed instruments that exploit the characteristics of a reproducible pulsed flow of solution. In this paper, we discuss our instrumental approaches and some applications that have benefited from the use of a reproducible pulsed flow rather than the traditional linear flow approach. To place our approach in the context of the continuously developing field of flow analysis, an overview of other programmed flow systems is also presented.
Publisher: Informa UK Limited
Date: 2012
Publisher: American Chemical Society (ACS)
Date: 2002
DOI: 10.1021/ED079P135.4
Publisher: American Chemical Society (ACS)
Date: 27-10-2001
DOI: 10.1021/OM010620O
Publisher: Informa UK Limited
Date: 02-1999
Publisher: Elsevier
Date: 2013
Publisher: Walter de Gruyter GmbH
Date: 1996
Publisher: Elsevier BV
Date: 10-2009
DOI: 10.1016/J.ACA.2009.06.023
Abstract: The introduction of ninhydrin treatment as a chemical technique for the visualisation of latent fingermarks on porous surfaces revolutionised approaches to forensic fingermark examination. Since then, a range of amino acid sensitive reagents has been developed and such compounds are in widespread use by law enforcement agencies worldwide. This paper reviews the development and use of these reagents for the detection of latent fingermarks on porous surfaces. A brief overview is provided, including an historical background, forensic significance, and a general approach to the development of latent fingermarks on porous surfaces. This is followed by a discussion of specific amino acid sensitive treatments.
Publisher: Elsevier BV
Date: 03-2006
Publisher: American Chemical Society (ACS)
Date: 10-2006
DOI: 10.1021/ED083P1465
Publisher: Royal Society of Chemistry (RSC)
Date: 1999
DOI: 10.1039/A902118C
Publisher: The University of Sydney Library
Date: 22-12-2022
DOI: 10.30722/IJISME.30.05.002
Abstract: Teaching assistants (TAs) have a major impact on the undergraduate science student experience, and therefore training TAs is critical to support engagement and learning. We ran a one-day TA training program for two years and found that participation in the program increased TAs’ reflective practice and student-centered teaching over a semester of teaching. Open-ended pre-survey responses indicated that in addition to wanting to learn pedagogical approaches, TAs sought help managing challenging situations and student behaviour. Post-surveys confirmed that the program fulfilled most learning goals of TAs and they subsequently applied the new teaching approaches. Participants indicated high levels of empowerment within their teaching roles across the cognitions of impact, competence and meaningfulness, but low self-determination. All aspects of empowerment increased with experience.
Publisher: AIP Publishing
Date: 15-11-1994
DOI: 10.1063/1.468070
Abstract: The collisional deactivation of highly vibrationally excited toluene-d0 and toluene-d8 by helium bath gas has been investigated using quasiclassical trajectory simulations. Collisional energy transfer was found to increase with initial toluene internal energy, in agreement with the experiments of Toselli and Barker [J. Chem. Phys. 97, 1809 (1992), and references therein]. The temperature dependence of 〈ΔE2〉1/2 is predicted to be T(0.44±0.10), in agreement with the experiments of Heymann, Hippler, and Troe [J. Chem. Phys. 80, 1853 (1984)]. Toluene is found to have no net angular-momentum (rotational-energy) transfer to helium bath gas, although 〈ΔJ2〉1/2 has a temperature dependence of T(0.31±0.07). Re-evaluation of earlier calculations [‘‘Paper I:’’ Lim, J. Chem. Phys. 100, 7385 (1994)] found that rotational energy transfer could be induced by increasing the mass of the collider, or by increasing the strength of the intermolecular interaction: in these cases, angular-momentum transfer depended on the initial excitation energy. In all cases, the final rotational distributions remained Boltzmann.
Publisher: Royal Society of Chemistry (RSC)
Date: 2000
DOI: 10.1039/B005118G
Publisher: Royal Society of Chemistry (RSC)
Date: 1997
DOI: 10.1039/A608119C
Publisher: AIP Publishing
Date: 06-1986
DOI: 10.1063/1.450754
Abstract: An a priori calculation of collisional energy transfer has been carried out, based on an extension of Gilbert’s ‘‘biased random walk’’ model [J. Chem. Phys. 80, 5501 (1984)]. The model assumes that energy migration during the collision is random except for certain physical and statistical constraints. It is shown that the probability of energy transfer can be obtained accurately from a relatively small number (10–50) of trajectories using a Smoluchowski equation and generalized Langevin equation approach. Calculations for the azulene/argon system, employing realistic inter- and intramolecular potentials, show excellent agreement with the experimental results of Rossi, Pladziewicz, and Barker [J. Chem. Phys. 78, 6695 (1983)] and Hippler, Lindemann, and Troe [J. Chem. Phys. 83, 3906 (1985)]. This suggests that the extended model may be reliably and economically used to calculate appropriate energy transfer quantities. Moreover, a number of general trends seen in experimental results can be rationalized with the model.
Publisher: Informa UK Limited
Date: 16-06-2015
Publisher: AIP Publishing
Date: 11-1988
DOI: 10.1063/1.455529
Abstract: The relaxation of a system of highly excited molecules can be described by a reaction/(de)activation master equation. Much work has been concentrated on the functional form of q(x,y), the probability of a reactant molecule starting with energy y and having final energy x after collision with a bathgas molecule. A recent study [J. Chem. Phys. 86, 1269 (1987)] suggests that an exponential q(x,y) is neccessary for linear decay. This Comment shows that such an exponential transition probability is merely sufficient. The linear decay is also predicted by a step-ladder model for q(x,y).
Publisher: AIP Publishing
Date: 08-1995
DOI: 10.1063/1.469725
Abstract: The use of quasiclassical simulations arises from practical considerations: It is not possible to do quantum simulations for most systems. By necessity, only quantum dynamics can reproduce all quantum properties. The use of restricted energy flows by using pseudoholonomic constraints to conserve ‘‘quantum’’ zero-point energy [J. Chem. Phys. 102, 1705 (1995)] is an attempt to reproduce at least one important quantum phenomenon using a (pseudo)classical method. Future applications for the pseudoholonomic-constraint method are discussed.
Publisher: American Chemical Society
Date: 29-11-2021
Publisher: Elsevier BV
Date: 30-04-2007
DOI: 10.1016/J.TALANTA.2006.11.032
Abstract: An investigation into the chemiluminescence of fourteen organic acids and tris(2,2'-bipyridyl)ruthenium(II) was undertaken. Particular emphasis was placed upon the method of production of the reagent, tris(2,2'-bipyridyl)ruthenium(III), with cerium(IV) sulfate, potassium permanganate, lead dioxide and electrochemical generation. Analytically useful chemiluminescence was observed when Ce(IV) or potassium permanganate were employed as oxidants. The kinetics of analyte oxidation was related to the intensity of the chemiluminescence emission, which increased by three orders of magnitude for tartaric acid after 40h of oxidation.
Publisher: Royal Society of Chemistry (RSC)
Date: 16-01-2002
DOI: 10.1039/B109074G
Publisher: Elsevier BV
Date: 05-2008
DOI: 10.1016/J.ACA.2008.03.009
Abstract: Further consideration has been given to the reaction pathway of a model peroxyoxalate chemiluminescence system. Again utilising doubly labelled oxalyl chloride and anhydrous hydrogen peroxide, 2D EXSY (13)C nuclear magnetic resonance (NMR) spectroscopy experiments allowed for the characterisation of unknown products and key intermediate species on the dark side of the peroxyoxalate chemiluminescence reaction. Exchange spectroscopy afforded elucidation of a scheme comprised of two distinct mechanistic pathways, one of which contributes to chemiluminescence. (13)C NMR experiments carried out at varied reagent molar ratios demonstrated that excess amounts of hydrogen peroxide favoured formation of 1,2-dioxetanedione: the intermediate that, upon thermolysis, has been long thought to interact with a fluorophore to produce light.
Publisher: Springer Berlin Heidelberg
Date: 2003
Publisher: Elsevier BV
Date: 2012
DOI: 10.1016/J.TALANTA.2011.11.051
Abstract: A simple controlled chemical reduction of 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) and related nitramine compounds with zinc amalgam generates species that elicit intense chemiluminescence with tris(2,2'-bipyridine)ruthenium(III), which extends this widely utilised chemiluminescence reagent to a new class of analyte and presents a sound chemical basis for a screening test for nitramine high explosives. Examination of the chemiluminescence profiles under stopped-flow conditions revealed contributions from multiple transient species formed in the initial reduction step.
Publisher: American Chemical Society (ACS)
Date: 10-02-2009
DOI: 10.1021/JA808401P
Abstract: Electron paramagnetic resonance spectroscopy has afforded the identification of a much postulated 1,4-dioxy biradical that occurs within the light producing pathway of peroxyoxalate chemiluminescence.
Publisher: Springer Singapore
Date: 2019
Publisher: Elsevier BV
Date: 02-1991
Publisher: American Chemical Society (ACS)
Date: 11-1992
DOI: 10.1021/JA00049A055
Publisher: American Chemical Society
Date: 2016
Publisher: Elsevier BV
Date: 08-10-2004
DOI: 10.1016/J.TALANTA.2004.02.031
Abstract: The spectral distribution for the chemiluminescent oxidation of ammonia with hypobromite is significantly different to that for the oxidation of ammonia with N-bromosuccinimide. Therefore, in contrast to the assumptions of several authors, the action of N-bromosuccinimide is not solely derived from the in situ formation of hypobromite. Neither the oxidation of urea with hypobromite nor the oxidation of urea with N-bromosuccinimide involves an initial hydrolysis of urea to ammonia in the alkaline solution. However, these two reactions lead to a common emitter. The addition of xanthene dyes, such as dichlorofluorescein, enhance the chemiluminescence intensity by energy transfer to the efficient fluorophore, but reaction between the sensitiser and hypobromite can result in a significant increase in the background signal. A list of potential interferences has been compiled particular attention was paid to guanidino compounds, as the chemiluminescence accompanying the oxidation of this functional group has not been previously discussed.
Publisher: Elsevier BV
Date: 10-2010
DOI: 10.1016/J.TALANTA.2010.07.064
Abstract: In this paper, we present our preliminary studies into naphthoquinones as novel reagents for the detection of latent fingermarks on paper. Latent fingermarks deposited on paper substrates were treated with solutions of selected naphthoquinones in ethyl acetate/HFE-7100, with subsequent heating. The selected compounds were 1,4-dihydroxy-2-naphthoic acid, 1,2-naphthoquinone-4-sulfonate, 2-methoxy-1,4-naphthoquinone and 2-methyl-1,4-naphthoquinone. All of the tested compounds yielded purple-brown visible fingermarks, which also exhibited photoluminescence when illuminated with a high intensity filtered light source at 555 nm and viewed through red goggles. Indirect heat using an oven at 150°C for 1h was found to be superior to direct heat with an iron, which while providing faster development lead to increased levels of background colouration. Luminescence spectrophotometry revealed differences in photoluminescence characteristics for fingermarks developed with the different naphthoquinones, with excitation over the range 530-590 nm. Luminescence spectrophotometry of developed lysine, glycine and serine spots on paper was used to confirm that the naphthoquinones were reacting with amino acids in the latent fingermark.
Publisher: Australasian Society for Computers in Learning in Tertiary Education
Date: 08-12-2000
DOI: 10.14742/AJET.1834
Abstract: span The use of computers is becoming more widespread in education and in the wider workforce. This communication reports the results of a survey of first year undergraduate students at Deakin University, conducted at the beginning of the 2000 academic year. The high penetration of IT usage in this university s le is similar to that of a recent survey of school students conducted by Meredyth et al. [ /span em Real Time: Computers, Change and Schooling, /em span DETYA, Canberra, 1999]. The present study indicates that the level of IT skills is variable. There is an urgent need for IT training for university students in order to achieve successful learning outcomes using IT and to satisfy the needs of future employers. /span
Publisher: The University of Sydney Library
Date: 31-12-2020
DOI: 10.30722/IJISME.28.04.001
Abstract: The undergraduate laboratory occupies a large fraction of science students’ time. Over 3000 students were asked to rate their laboratory learning experience using 12 metrics. 362 academics were asked to predict which of these 12 aspects of the student experience would correlate with the overall laboratory learning experience. Responses from academics in biology, chemistry and physics departments, and from the USA and Australia, are statistically the same. However, the correlation between these staff predictions and student results is poor. The student results are consistent with extant educational research, but it appears that these findings are not reaching those who are responsible for developing undergraduate laboratory courses. There is a great need for educational research to be made more accessible for academics who are trained in scientific, but not in educational research.
Publisher: Royal Society of Chemistry (RSC)
Date: 27-02-2002
DOI: 10.1039/B200794K
Abstract: This paper describes, for the first time, a simple and effective synthetic route for covalently bonding the chemiluminescence reagent, (4-[4-(dichloromethylsilanyl)-butyl]-4'-methyl-2,2'-bipyridyl)bis(2,2'-bipyridyl)ruthenium(II) onto silica particles. The subsequent preparation of chemically regeneratable detection cells and their preliminary analytical evaluation with both sequential injection analysis and flow injection analysis are also reported. Unoptimised analytical figures of merit were established for standard solutions of codeine and sodium oxalate with detection limits calculated from three times the standard deviation of the blank signal, of 1 x 10(-8) M and 3 x 10(-7) M respectively. The chemically immobilised reagent exhibited some intriguing solvent and kinetic effects, which are also briefly discussed.
Publisher: Elsevier BV
Date: 11-1988
Publisher: Royal Society of Chemistry (RSC)
Date: 2003
DOI: 10.1039/B305721F
Publisher: Informa UK Limited
Date: 11-03-2022
Publisher: American Chemical Society (ACS)
Date: 03-1995
DOI: 10.1021/J100013A024
Publisher: American Chemical Society (ACS)
Date: 10-2008
DOI: 10.1021/ED085P1347
Publisher: AIP Publishing
Date: 06-1991
DOI: 10.1063/1.460724
Abstract: The kinetics of some gas-phase alcohol/alkoxide proton-transfer reactions is slower than predicted by simple Rice–Ramsberger–Kassel–Marcus (RRKM) rate theory modeling on the near-barrierless reaction surfaces. Reaction dynamics can be investigated in isolation from nonequilibrium and/or thermodynamic considerations through the study of a generic isoergic ion–molecule system X−+X−H. Monte Carlo quasiclassical trajectory simulations on barrierless reaction surfaces show that the slow experimental kinetics is consistent with both (i) locking of the external rotations of the reactants and (ii) passage over the (orbital angular momentum) centrifugal barrier being the rate-determining steps in bimolecular association, rather than only the latter process. In addition, there may be non-RRKM product selectivity.
Publisher: AIP Publishing
Date: 02-1990
DOI: 10.1063/1.458064
Abstract: Data from classical trajectory simulations of the collision of a highly excited molecule with a monatomic bath gas are used to test the validity of the precepts used in the biased-random-walk (BRW) model for collisional energy transfer. This model assumes that energy migration during the collision is pseudorandom except for the constraint of microscopic reversibility, and leads to a simple displaced Gaussian form for the energy-transfer probability distribution. The BRW assumptions are shown to be of acceptable validity to exact classical trajectory simulations. A simple analytical approximation to the mean-square energy transfer per collision is obtained which reproduces the trajectory data to within an average of ±20%, and also gives acceptable accord with experimental data. The model shows that the magnitude of the average energy transferred per collision is governed by the time taken to traverse the overall interaction potential in and out from the appropriate collision diameter, by the internal energy, and by the average force exerted at the classical turning point of in idual reactant-atom–bath-gas interactions.
Publisher: Elsevier
Date: 2013
Publisher: AIP Publishing
Date: 08-01-1997
DOI: 10.1063/1.473396
Abstract: Quasiclassical trajectory calculations offer a cost-effective means of investigating the dynamics of chemical reactions. However, they suffer from the zero-point energy (ZPE) problem, whereby the (quantum) ZPE motion can contribute to an overestimation of the rate coefficient. This paper reports on some dynamics of the Hénon–Heiles system. Dynamics of the water molecule at energies just below the (quantum) dissociation threshold, are also reported. The TRAPZ method [Lim and McCormack, J. Chem. Phys. 102, 1705 (1995)] leads to a definite improvement over unconstrained classical mechanics.
Publisher: American Chemical Society (ACS)
Date: 2005
DOI: 10.1021/ED082P145
Publisher: Elsevier BV
Date: 05-2002
Publisher: Elsevier BV
Date: 07-2013
Publisher: Royal Society of Chemistry (RSC)
Date: 2000
DOI: 10.1039/A909614K
Publisher: Royal Society of Chemistry (RSC)
Date: 1999
DOI: 10.1039/A903098K
Publisher: Elsevier BV
Date: 09-1996
Publisher: American Chemical Society (ACS)
Date: 08-2005
DOI: 10.1021/ED082P1263.2
Publisher: AIP Publishing
Date: 22-01-1995
DOI: 10.1063/1.468697
Abstract: We propose a computational technique to constrain the vibrational modes of a classical molecule to have energy greater than the quantum zero-point energy (ZPE). The trajectory of any mode with energy less than ZPE is projected to a neighboring point in phase space where the energy is equal to the ZPE and the phase angle of the mode is unchanged. All other modes are then perturbed in such a way as to conserve the total energy of the system. This technique is similar in principle to the method of holonomic constraints. We apply this ‘‘semiholonomic’’ TRAPZ (trajectory projection onto ZPE orbit) scheme to the two mode Hénon–Heiles system and find that it results in a decrease of ergodicity. Periodic limit cycle internal vibrational energy redistribution is observed. Implications of this method for the conservation of ZPE in quasiclassical trajectory simulations are discussed.
Publisher: Queensland University of Technology
Date: 19-02-2010
DOI: 10.5204/JLD.V3I3.58
Publisher: IOP Publishing
Date: 27-09-2022
Abstract: Undergraduate first-year courses are often mandatory for students in a variety of majors and degrees. Many students view these core courses as of little interest and relevance, which is associated with lack of motivation for study and can lead to cheating. Contract cheating in text-based is difficult to detect and prove. Contract cheating in numerical-calculation-based assessments is even harder to detect and prove. This paper discusses how unique identifying information can be incorporated into numerical assessments and how unique data sets can be used to both detect and prove contract cheating. Finally, some measures to discourage contract cheating are discussed.
Publisher: American Chemical Society (ACS)
Date: 03-05-2013
DOI: 10.1021/JP312603M
Abstract: The emission of light from the permanganate-oxalate reaction enables monitoring of intermediates not accessible through traditional spectrophotometric interrogation. Despite the inherent complexity of the underlying chemical reactions and equilibria, the emission intensity-time profile was characterized by a simple model combining previously independent minimalistic descriptions of chemiluminescence and autocatalysis. The generation of the electronically excited [Mn(II)]* emitter and the acceleration of the reaction even in the presence of high initial concentrations of Mn(II) (under conditions that preclude accumulation of colloidal Mn(IV)) provide new evidence for the reduction of manganese species by a reactive radical intermediate as a supplementary positive feedback loop to the formation of Mn(II).
No related grants have been discovered for Kieran Fergus Lim.