ORCID Profile
0000-0003-1094-0947
Current Organisations
University of Adelaide
,
Monash University
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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)
Physical Chemistry (Incl. Structural) | Chemical Spectroscopy | Structural Chemistry and Spectroscopy | Interdisciplinary Engineering Not Elsewhere Classified | Nanotechnology | Physical Chemistry of Materials | Colloid And Surface Chemistry | Colloid and Surface Chemistry | Chemical Thermodynamics and Energetics | Sensor (Chemical And Bio-) Technology | Fluidization And Fluid Mechanics | Characterisation Of Macromolecules | Theoretical and Computational Chemistry | Quantum Chemistry | Instruments And Techniques | Optical Physics Not Elsewhere Classified | Supramolecular Chemistry | Energy Generation, Conversion and Storage Engineering | Physical Chemistry not elsewhere classified | Nanotechnology | Genome Structure | Interdisciplinary Engineering | Surfaces and Structural Properties of Condensed Matter | Nanofabrication, Growth and Self Assembly
ANZSRC Socio-Economic Objective (SEO)
Chemical sciences | Physical sciences | Scientific instrumentation | Expanding Knowledge in the Chemical Sciences | Plastic products (incl. Construction materials) | Medical instrumentation | Expanding Knowledge in Technology | Hydrogen Production from Renewable Energy | Concentrating processes of other base metal ores | Solar-Photovoltaic Energy | Field crops not elsewhere classified | Water services and utilities | Expanding Knowledge in the Physical Sciences | Transport equipment |
Related Links
Publications
Photoionization of Nb3CO and Nb3(CO)2: Is CO Molecularly or Dissociatively Adsorbed on Niobium?
Publisher: American Chemical Society (ACS)
Date: 16-01-2004
DOI: 10.1021/JP036041+
Rotational and hyperfine analysis of the a′3Φ4 -x3Φ4 transitions of coh and cod
Publisher: Elsevier BV
Date: 09-1995
Simple and high-yield preparation of carbon-black-supported ∼1 nm platinum nanoclusters and their oxygen reduction reactivity
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1NR04202E
Abstract: This work established a simple method for the size-selective synthesis of a series of ligand-protected platinum nanoclusters with superior oxygen reduction reactivity.
Investigation of the Diffusion of Cr2O3 into Different Phases of TiO2 upon Annealing
Publisher: American Chemical Society (ACS)
Date: 05-01-2021
Density-functional tight-binding for phosphine-stabilized nanoscale gold clusters
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0SC04514D
Abstract: We report a parameterization of the density-functional tight-binding (DFTB) method for the accurate prediction of molecular, electronic and vibrational structure of phosphine-ligated nanoscale gold clusters, metalloids, and gold surfaces.
Red-Light-Mediated Photocatalytic Hydrogen Evolution by Hole Transfer from Non-Fullerene Acceptor Y6
Publisher: American Chemical Society (ACS)
Date: 23-08-2022
Infrared Laser Desorption of Hydroquinone from a Water−Ethanol Liquid Beam
Publisher: American Chemical Society (ACS)
Date: 19-07-2003
DOI: 10.1021/JP022248B
The Electronic Spectrum of Gaseous CoO in the Visible Region
Publisher: Elsevier BV
Date: 12-1997
Abstract: Laser excitation spectra of gaseous CoO have been recorded using Doppler-limited intracavity spectroscopy and supersonic jet-cooled molecular beam methods. As seen in the molecular beam spectra there are nearly 100 bands arising from the X4Delta7/2 spin component of the ground state in the wavelength region 430-720 nm. All of them are very strongly red-degraded and most of them are perturbed. 59Co hyperfine broadenings or splittings have been observed in many. The bands can be arranged into five electronic transitions, together with a considerable number of "extra" bands induced by perturbations two of the excited electronic states are 4Phi, while the other three, which lie within 1700 cm-1, are 4Delta. Semi-empirical calculations have been carried out for the 4Delta excited states, using exchange integrals transferred from the TiO and VO spectra the predicted energies, spin-orbit structures, and relative intensities in absorption are consistent with the assignment of all three 4Delta states to the same electron configuration, (4ssigma)1(3ddelta)3(3dpi)2(3dsigma)1. It seems that there are extensive interactions between the excited 4Delta states, because only one of them gives rise to a recognizable, though irregular, long vibrational progression in absorption. The other two progressions die out abruptly and unexpectedly after three or four members, presumably as a result of interference effects however, wavelength-resolved fluorescence studies, together with calculations of the Franck-Condon overlap integrals to the various vibrational levels of the ground state, show that the upper state progressions reappear following a region of confused absorption. All of the excited states show highly irregular variations of their vibrational intervals and rotational constants with the vibrational quantum number, v. The wavelength-resolved fluorescence spectra give evidence for new low-lying electronic states of CoO at 3038, 5989, and 9105 cm-1 based on its vibrational frequency the 3038 cm-1 state is possibly the sigmadelta4pi2 B4Sigma- state. Copyright 1997 Academic Press. Copyright 1997Academic Press
Use of a heated nozzle to locate the hot bands in the 340-260-nm absorption of sulfur dioxide
Publisher: American Chemical Society (ACS)
Date: 1990
DOI: 10.1021/J100364A010
DFT Calculations on Group 5 Mixed Metal Tetramers: TaxNbyVz (x + y + z = 4)
Publisher: CSIRO Publishing
Date: 2004
DOI: 10.1071/CH04122
Abstract: We report Density Functional Theory (DFT) calculations on mixed-metal tetramers comprised of the Group 5 (Vb) elements V, Nb, and Ta. Our results show that the lowest energy structures for Nb4 and Ta4 are regular tetrahedra with Td symmetry and singlet multiplicity whereas V4 is a triplet state with C2v symmetry. The monosubstituted isomers, A3B, all have C3v symmetry but several higher energy Cs structures have been found that are approximately 100 kJ mol−1 higher in energy. The disubstituted isomers all posses arachno-butterfly structures the A2B2 types with C2v symmetry and the A2BC types with Cs symmetry. However, the relative openness of the arachno structures is found to be specific to the composition of the mixed-metal cluster.
Aggregation Behavior of Ligand-Protected Au9 Clusters on Sputtered Atomic Layer Deposition TiO2
Publisher: American Chemical Society (ACS)
Date: 09-03-2017
2Π-X̃2Σ+ electronic bands of titanium methylidyne, TiCH, near 725 nm wavelength
Publisher: Elsevier BV
Date: 1997
Neutral tantalum-carbide clusters: A multiphoton ionization and density functional theory study
Publisher: American Chemical Society (ACS)
Date: 22-03-2000
DOI: 10.1021/JP993489V
Rotational and hyperfine structure of some low-J lines in the A3Φ-X3Δ (0,0) band of TiO
Publisher: Elsevier BV
Date: 12-1996
Abstract: Genome-wide association studies coupled with large-scale replication and fine-scale mapping studies have identified more than 150 genomic regions that are associated with breast cancer risk. Here, we review efforts to translate these findings into a greater understanding of disease mechanism. Our review comes in the context of a recently published fine-scale mapping analysis of these regions, which reported 352 independent signals and a total of 13,367 credible causal variants. The vast majority of credible causal variants map to noncoding DNA, implicating regulation of gene expression as the mechanism by which functional variants influence risk. Accordingly, we review methods for defining candidate-regulatory sequences, methods for identifying putative target genes and methods for linking candidate-regulatory sequences to putative target genes. We provide a summary of available data resources and identify gaps in these resources. We conclude that while much work has been done, there is still much to do. There are, however, grounds for optimism combining statistical data from fine-scale mapping with functional data that are more representative of the normal "at risk" breast, generated using new technologies, should lead to a greater understanding of the mechanisms that influence an in idual woman's risk of breast cancer.
Density functional theory investigation of Cu(I)- and Cu(II)-curcumin complexes
Publisher: Wiley
Date: 20-08-2011
DOI: 10.1002/JCC.21631
Abstract: Density functional theory is used to obtain the lowest energy geometries of bis-aqua curcumin complexes and bis-curcumin complexes of Cu(I) and Cu(II). Three conformations of curcumin, obtained by rotation of the substituted aromatic groups, were considered in each case. Steric repulsion, due to the methoxy–methoxy interactions, was found to be an important factor in determining the lowest energy conformer of Cu(II)(curcumin)2 but was less important for the Cu(I) analog. Using a sufficiently large basis set, the results show that the lowest energy Cu(II)(curcumin)2 geometry is square planar around the copper atom, in contrast to the results from a previous study (Shen et al. THEOCHEM-J Mol Struct 2005, 757, 199). In addition, other studies suggested that the formation of this complex is followed by the reduction of Cu(II) to Cu(I). We also examined the singly occupied molecular orbital, spin density, and natural bond orbitals of Cu(II)(curcumin)2. While the former two analyses show little evidence of electron transfer from curcumin into the Cu center, the latter indicates that Cu(II) is partially reduced to Cu(I) as a consequence of complexation. Finally, we consider the bis-aqua curcumin and bis-curcumin complexes on a reaction path involving progressive displacement of water molecules by curcumin ligands. The results show that the bis-curcumin complex is the most stable Cu(II) complex, showing consistently exothermic steps in the reaction path. However, for Cu(I), the final step in the reaction path is essentially thermoneutral, indicating that the 1:1 and 1:2 Cu(I) complexes are equally stable thermodynamically.
Au101–rGO nanocomposite: immobilization of phosphine-protected gold nanoclusters on reduced graphene oxide without aggregation
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D0NA00927J
Abstract: A method is presented for the deposition of gold clusters onto reduced graphene oxide, without aggregation of the gold clusters.
A Density Functional Theory Investigation of the Bimetallic Clusters Nb2Rh and NbRh2 and the Complexes They Form with CO
Publisher: CSIRO Publishing
Date: 2011
DOI: 10.1071/CH11179
Abstract: The interaction of CO with the bimetallic clusters Nb2Rh and NbRh2 has been theoretically investigated using density functional theory. The lowest energy structure of Nb2Rh is found to be a doublet Cs scalene triangle and the global minimum of Nb2Rh–CO is a dissociative structure with C1 symmetry. The lowest energy minimum of NbRh2 is found to be a doublet C2v isosceles triangle and the global minimum of NbRh2–CO is a dissociative structure with Cs symmetry. In comparison with our previous work on Rh3 + CO (J. Comp. Chem., 2008, 29, 1497), these results show that substitution of a single Rh atom with Nb is sufficient to dissociate CO.
Determination of the molecular structure of diacetylene from high-resolution FTIR spectroscopy
Publisher: Springer Science and Business Media LLC
Date: 02-1995
DOI: 10.1007/BF02263527
Investigating Pt Atom Addition to Gas Phase Ce2On Clusters Using Photoionization Efficiency Spectroscopy and Density Functional Theory
Publisher: American Chemical Society (ACS)
Date: 25-11-2020
The Optical Spectrum of a Large Isolated Polycyclic Aromatic Hydrocarbon: Hexa- peri -hexabenzocoronene, C 42
Publisher: American Astronomical Society
Date: 17-06-2008
DOI: 10.1086/590207
Cr2O3 layer inhibits agglomeration of phosphine-protected Au9 clusters on TiO2 films
Publisher: AIP Publishing
Date: 26-10-2021
DOI: 10.1063/5.0059912
Abstract: The properties of semiconductor surfaces can be modified by the deposition of metal clusters consisting of a few atoms. The properties of metal clusters and of cluster-modified surfaces depend on the number of atoms forming the clusters. Deposition of clusters with a monodisperse size distribution thus allows tailoring of the surface properties for technical applications. However, it is a challenge to retain the size of the clusters after their deposition due to the tendency of the clusters to agglomerate. The agglomeration can be inhibited by covering the metal cluster modified surface with a thin metal oxide overlayer. In the present work, phosphine-protected Au clusters, Au9(PPh3)8(NO3)3, were deposited onto RF-sputter deposited TiO2 films and subsequently covered with a Cr2O3 film only a few monolayers thick. The s les were then heated to 200 °C to remove the phosphine ligands, which is a lower temperature than that required to remove thiolate ligands from Au clusters. It was found that the Cr2O3 covering layer inhibited cluster agglomeration at an Au cluster coverage of 0.6% of a monolayer. When no protecting Cr2O3 layer was present, the clusters were found to agglomerate to a large degree on the TiO2 surface.
Reaction pathways of singlet silylene and singlet germylene with water, methanol, ethanol, dimethyl ether, and trifluoromethanol: An ab initio molecular orbital study
Publisher: American Chemical Society (ACS)
Date: 25-01-2001
DOI: 10.1021/JP002873L
Ab initio calculations on excited states of VCH
Publisher: Elsevier BV
Date: 08-2000
On the conservation of angular momentum in polyatomic photochemical reactions: H2 Co (v, J, Ka , Kc ) → H + HCO (N, Ka , Kc , J)
Publisher: SPIE
Date: 15-05-1998
DOI: 10.1117/12.308415
Investigating Charge Transfer Interactions in AuCe2On Clusters Using Photoionization Efficiency Spectroscopy and Density Functional Theory
Publisher: American Chemical Society (ACS)
Date: 08-11-2019
Abstract: The properties of small cerium oxide and gold-cerium oxide clusters were explored as analogues for gold deposition at defect sites on a cerium oxide surface. Ce
Inside Cover: Creation of High‐Performance Heterogeneous Photocatalysts by Controlling Ligand Desorption and Particle Size of Gold Nanocluster (Angew. Chem. Int. Ed. 39/2021)
Publisher: Wiley
Date: 12-07-2021
Chemically synthesised atomically precise gold clusters deposited and activated on titania. Part II
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3CP52497C
Abstract: Synchrotron XPS was used to investigate a series of chemically synthesised, atomically precise gold clusters Au(n)(PPh3)y (n = 8, 9 and 101, y depending on the cluster size) immobilized on anatase (titania) nanoparticles. Effects of post-deposition treatments were investigated by comparison of untreated s les with analogues that have been heat treated at 200 °C in O2, or in O2 followed by H2 atmosphere. XPS data shows that the phosphine ligands are oxidised upon heat treatment in O2. From the position of the Au 4f(7/2) peak it can be concluded that the clusters partially agglomerate immediately upon deposition. Heating in oxygen, and subsequently in hydrogen, leads to further agglomeration of the gold clusters. It is found that the pre-treatment plays a crucial role in the removal of ligands and agglomeration of the clusters.
Onset of carbon-carbon bonding in Ta5C3, (y = 0-6) clusters: A threshold photoionization and density functional theory study
Publisher: American Chemical Society (ACS)
Date: 03-2010
DOI: 10.1021/JP100118R
Abstract: We have used photoionization efficiency spectroscopy to determine ionization energies (IEs) of the gas-phase tantalum-carbide clusters Ta(5)C(y) (y = 0-6). The structures of the clusters observed in the experiment are assigned by comparing the experimental IEs with those of candidate isomers, calculated by density functional theory. Two competing geometries of the underlying Ta(5) cluster are found to be present in the assigned Ta(5)C(y) structures either a "prolate" or "distorted oblate" trigonal bipyramid geometry. The onset of carbon-carbon bonding in the Ta(5)C(y) series is proposed to occur at y = 6, with the structure of Ta(5)C(6) containing two molecular C(2) units.
Carbon Nitride Loaded with an Ultrafine, Monodisperse, Metallic Platinum‐Cluster Cocatalyst for the Photocatalytic Hydrogen‐Evolution Reaction
Publisher: Wiley
Date: 24-04-2023
Abstract: For the realization of a next‐generation energy society, further improvement in the activity of water‐splitting photocatalysts is essential. Platinum (Pt) is predicted to be the most effective cocatalyst for hydrogen evolution from water. However, when the number of active sites is increased by decreasing the particle size, the Pt cocatalyst is easily oxidized and thereby loses its activity. In this study, a method to load ultrafine, monodisperse, metallic Pt nanoclusters (NCs) on graphitic carbon nitride is developed, which is a promising visible‐light‐driven photocatalyst. In this photocatalyst, a part of the surface of the Pt NCs is protected by sulfur atoms, preventing oxidation. Consequently, the hydrogen‐evolution activity per loading weight of Pt cocatalyst is significantly improved, 53 times, compared with that of a Pt‐cocatalyst loaded photocatalyst by the conventional method. The developed method is also effective to enhance the overall water‐splitting activity of other advanced photocatalysts such as SrTiO 3 and BaLa 4 Ti 4 O 15 .
Photodetachment velocity map imaging of the 1A′ ←2A′ transition in the AuOH anion
Publisher: Elsevier BV
Date: 04-2015
Identification of the Vibrational Modes in the Far-Infrared Spectra of Ruthenium Carbonyl Clusters and the Effect of Gold Substitution
Publisher: American Chemical Society (ACS)
Date: 23-04-2014
DOI: 10.1021/IC403040U
Abstract: High-quality far-IR absorption spectra for a series of ligated atomically precise clusters containing Ru3, Ru4, and AuRu3 metal cores have been observed using synchrotron radiation, the latter two for the first time. The experimental spectra are compared with predicted IR spectra obtained following complete geometric optimization of the full cluster, including all ligands, using DFT. We find strong correlations between the experimental and predicted transitions for the low-frequency, low-intensity metal core vibrations as well as the higher frequency and intensity metal-ligand vibrations. The metal core vibrational bands appear at 150 cm(-1) for Ru3(CO)12, and 153 and 170 cm(-1) for H4Ru4(CO)12, while for the bimetallic Ru3(μ-AuPPh3)(μ-Cl)(CO)10 cluster these are shifted to 177 and 299 cm(-1) as a result of significant restructuring of the metal core and changes in chemical composition. The computationally predicted IR spectra also reveal the expected atomic motions giving rise to the intense peaks of metal-ligand vibrations at ca. 590 cm(-1) for Ru3, 580 cm(-1) for Ru4, and 560 cm(-1) for AuRu3. The obtained correlations allow an unambiguous identification of the key vibrational modes in the experimental far-IR spectra of these clusters for the first time.
Dispersed emission from the lower vibronic levels of the Ã1 A2 state of sulfur dioxide
Publisher: Elsevier BV
Date: 1997
Chemically-synthesised, atomically-precise gold clusters deposited and activated on titania
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3CP44005B
Abstract: Synchrotron XPS was used to investigate a series of chemically-synthesised, atomically-precise gold clusters Au(n)(PPh(3))(y) (n = 8, 9, 11 and 101, with y depending on cluster size) immobilized on titania nanoparticles. The gold clusters were washed with toluene at 100 °C or calcined at 200 °C to remove the organic ligand. From the position of the Au 4f(7/2) peak it is concluded that cluster size is not altered through the deposition. From the analysis of the phosphorous spectra, it can be concluded that the applied heat treatment removes the organic ligands. Washing and calcination leads to partial oxidation and partial agglomeration of the clusters. Oxidation of the clusters is most likely due to the interaction of the cluster core with the oxygen of the titania surface after removal of ligands. The position of the Au 4f(7/2) peak indicates that the size of the agglomerated clusters is still smaller than that of Au(101).
Influence of Surfactant Concentration on Laser-Based Gold Nanoparticle Formation and Stability
Publisher: CSIRO Publishing
Date: 2012
DOI: 10.1071/CH11366
Abstract: The time evolution of gold nanoparticle (AuNP) yields by in-situ laser irradiation from bulk gold in aqueous solutions containing the surfactant sodium dodecylsulfate (SDS) at concentrations above and below the critical micelle concentration in water is reported. These studies are augmented by transmission electron microscopy images of AuNP s les at each SDS concentration recorded after 90 min of laser irradiation. The results show that while a low concentration of SDS plays a role in the formation kinetics, there is no apparent influence of the SDS concentration around the surfactant critical micelle concentration on particle size during AuNP production.
Creation of High‐Performance Heterogeneous Photocatalysts by Controlling Ligand Desorption and Particle Size of Gold Nanocluster
Publisher: Wiley
Date: 07-2021
Abstract: Recently, the creation of new heterogeneous catalysts using the unique electronic/geometric structures of small metal nanoclusters (NCs) has received considerable attention. However, to achieve this, it is extremely important to establish methods to remove the ligands from ligand‐protected metal NCs while preventing the aggregation of metal NCs. In this study, the ligand‐desorption process during calcination was followed for metal‐oxide‐supported 2‐phenylethanethiolate‐protected gold (Au) 25‐atom metal NCs using five experimental techniques. The results clearly demonstrate that the ligand‐desorption process consists of ligand dissociation on the surface of the metal NCs, adsorption of the generated compounds on the support and desorption of the compounds from the support, and the temperatures at which these processes occurred were elucidated. Based on the obtained knowledge, we established a method to form a metal‐oxide layer on the surface of Au NCs while preventing their aggregation, thereby succeeding in creating a water‐splitting photocatalyst with high activity and stability.
Transfer of Ordered Phospholipid Films onto Solid Substrates from a Drained Foam Film
Publisher: American Chemical Society (ACS)
Date: 21-09-2015
Reduction and Diffusion of Cr-Oxide Layers into P25, BaLa4Ti4O15, and Al:SrTiO3 Particles upon High-Temperature Annealing
Publisher: American Chemical Society (ACS)
Date: 12-03-2023
Reaction rate constants for singlet silylene and singlet germylene with water, methanol, ethanol, dimethyl ether and trifluoromethanol: Competition between H-atom migration and H2 elimination
Publisher: CSIRO Publishing
Date: 2001
DOI: 10.1071/CH01040
A Review of State of the Art in Phosphine Ligated Gold Clusters and Application in Catalysis
Publisher: Wiley
Date: 25-03-2022
Abstract: Atomically precise gold clusters are highly desirable due to their well‐defined structure which allows the study of structure–property relationships. In addition, they have potential in technological applications such as nanoscale catalysis. The structural, chemical, electronic, and optical properties of ligated gold clusters are strongly defined by the metal–ligand interaction and type of ligands. This critical feature renders gold–phosphine clusters unique and distinct from other ligand‐protected gold clusters. The use of multidentate phosphines enables preparation of varying core sizes and exotic structures beyond regular polyhedrons. Weak gold–phosphorous (Au–P) bonding is advantageous for ligand exchange and removal for specific applications, such as catalysis, without agglomeration. The aim of this review is to provide a unified view of gold–phosphine clusters and to present an in‐depth discussion on recent advances and key developments for these clusters. This review features the unique chemistry, structural, electronic, and optical properties of gold–phosphine clusters. Advanced characterization techniques, including synchrotron‐based spectroscopy, have unraveled substantial effects of Au–P interaction on the composition‐, structure‐, and size‐dependent properties. State‐of‐the‐art theoretical calculations that reveal insights into experimental findings are also discussed. Finally, a discussion of the application of gold–phosphine clusters in catalysis is presented.
Photoionization efficiency spectroscopy and density functional theory investigations of RhHo2On (n=–2) clusters
Publisher: AIP Publishing
Date: 28-04-2009
DOI: 10.1063/1.3120442
Abstract: The experimental and theoretical adiabatic ionization energies (IEs) of the rhodium-holmium bimetallic clusters RhHo2On (n=0–2) have been determined using photoionization efficiency spectroscopy and density functional theory (DFT) calculations. Both sets of data show the IE of RhHo2O to be significantly lower than the values for RhHo2 and RhHo2O2, which are found to be similar. This indicates that there are significant changes in electronic properties upon sequential addition of oxygen atoms to RhHo2. The DFT investigations show that the lowest energy neutral structures are a C2v triangle for RhHo2, a C2v planar structure for RhHo2O where the O atom is doubly bridged to the Ho–Ho bond, and a C2v nonplanar structure for RhHo2O2, where the O2 is dissociative and each O atom is doubly bridged to the Ho–Ho bond in the cluster above and below the RhHo2 trimer plane. Good correlation between the experimental and computational IE data imply that the lowest energy neutral structures calculated are the most likely isomers ionized in the molecular beam. In particular, the theoretical adiabatic IE for the dissociative RhHo2O2 structure is found to compare better with the experimentally determined value than the corresponding lowest energy O2 associative structure.
Optical-optical double resonance spectroscopy of jet-cooled TiO: New 3Φ and 3Π states near 4 eV
Publisher: Elsevier BV
Date: 1997
The effect of counter ions on the far-infrared spectra of tris(triphenylphosphinegold)oxonium dimer salts
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5RA11599J
Abstract: The far-infrared spectra of two tris(triphenylphosphinegold)oxonium dimer salts in the 50–800 cm −1 region were recorded using synchrotron-based IR radiation, and comprehensively assigned utilising density functional theory calculations.
Laser-Based Formation and Properties of Gold Nanoparticles in Aqueous Solution: Formation Kinetics and Surfactant-Modified Particle Size Distributions
Publisher: American Chemical Society (ACS)
Date: 17-05-2010
DOI: 10.1021/JP9118315
Prediction and Kinetic Stabilization of Sn(II)-Perovskite Oxide Nanoshells
Publisher: American Chemical Society (ACS)
Date: 30-08-2022
Facile Decarboxylation of Propiolic Acid on a Ruthenium Center and Related Chemistry
Publisher: American Chemical Society (ACS)
Date: 08-2012
DOI: 10.1021/OM300157W
Pt Nanocluster Co-Catalysts for Photocatalytic Water Splitting
Publisher: MDPI AG
Date: 22-11-2018
DOI: 10.3390/C4040064
Abstract: Degussa P25 is a benchmark form of TiO2 used worldwide in photocatalysis studies. Currently, no such benchmark exists for co-catalysts, which are essential for many photocatalytic reactions. Here, we present the preparation of Pt nanocluster co-catalysts on TiO2 using an unmodified commercial source and equipment that is commonly available. Transmission electron microscopy reveals that the procedure produces TiO2 decorated with Pt atoms and nanoclusters (1–5 atoms). Optical reflectance and X-ray diffraction measurements show that the procedure does not affect the TiO2 polymorph or ultraviolet-visible (UV-Vis) absorbance. Gas phase photocatalytic splitting of heavy water (D2O) shows that the Pt nanocluster-decorated TiO2 outperforms Pt nanoparticle (produced by photodeposition) decorated TiO2 in D2 production. Pt nanoclusters, produced directly from a commercial source, with high co-catalyst activity, are prime candidates to be used in benchmark photocatalytic reactions.
Atomically resolved structure of ligand-protected Au9 clusters on TiO2 nanosheets using aberration-corrected STEM
Publisher: AIP Publishing
Date: 17-03-2016
DOI: 10.1063/1.4943203
Abstract: Triphenylphosphine ligand-protected Au9 clusters deposited onto titania nanosheets show three different atomic configurations as observed by scanning transmission electron microscopy. The configurations observed are a 3-dimensional structure, corresponding to the previously proposed Au9 core of the clusters, and two pseudo-2-dimensional (pseudo-2D) structures, newly found by this work. With the help of density functional theory (DFT) calculations, the observed pseudo-2D structures are attributed to the low energy, de-ligated structures formed through interaction with the substrate. The combination of scanning transmission electron microscopy with DFT calculations thus allows identifying whether or not the deposited Au9 clusters have been de-ligated in the deposition process.
Investigation of Ligand-Stabilized Gold Clusters on Defect-Rich Titania
Publisher: American Chemical Society (ACS)
Date: 07-12-2017
Threshold photoionization and density functional theory studies of bimetallic-carbide nanocrystals and fragments: Ta3ZrCy (y=–4)
Publisher: AIP Publishing
Date: 23-06-2009
DOI: 10.1063/1.3154384
Abstract: Gas-phase bimetallic tantalum-zirconium-carbide clusters are generated using a constructed double ablation cluster source. The Ta3ZrCy (y=0–4) clusters are examined by photoionization efficiency spectroscopy to extract experimental ionization energies (IEs). The IE trend for the Ta3ZrCy cluster series is reasonably similar to that of the Ta4Cy cluster series [V. Dryza et al., J. Phys. Chem. A 109, 11180 (2005)], although the IE reductions upon carbon addition are greater for the former. Complementary density functional theory calculations are performed for the various isomers constructed by attaching carbon atoms to the different faces of the tetrahedral Ta3Zr cluster. The good agreement between the experimental IE trend and that calculated for these isomers support a 2×2×2 face centered cubic nanocrystal structure for Ta4ZrC4 and nanocrystal fragment structures for the smaller clusters.
Influence of Cationic Surfactants on the Formation and Surface Oxidation States of Gold Nanoparticles Produced via Laser Ablation
Publisher: American Chemical Society (ACS)
Date: 24-09-2013
DOI: 10.1021/LA402234K
Abstract: We report on the time evolution of gold nanoparticles produced by laser ablation in the presence of the cationic surfactants cetyltrimethylammonium bromide (CTAB) and cetyltrimethylammonium chloride (CTAC) in aqueous solution. The broader applicability of a laser-induced nanoparticle formation kinetic model previously developed by us for the case of anionic surfactants in aqueous solution [ J. Phys. Chem. C 2010 , 114 , 15931 - 15940 ] is shown to also apply in the presence of cationic surfactants. We explore the surface properties of the nanoparticles produced in the presence of the cationic surfactants via synchrotron X-ray photoelectron spectroscopy (XPS). The XPS data indicate that at CTA(+) concentrations approximating the aqueous critical micelle concentration Au(III) is present on the nanoparticle surface. Such oxidation is not observed at (i) lower CTA(+) concentrations, (ii) in the presence of an anionic surfactant, or (iii) in the case of pure water as a solvent.
Surfactant Effects on Hydrogen Evolution by Small-Molecule Nonfullerene Acceptor Nanoparticles
Publisher: American Chemical Society (ACS)
Date: 23-08-2022
Self-sorting of porous Cu4L2L′2 metal–organic cages composed of isomerisable ligands
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D0CC08076D
Abstract: Structural asymmetry is introduced into porous Cu 4 L 4 metal–organic cages through the crystallisation-driven convergence of a dynamic combinatorial library.
Structural rearrangement in gas phase niobium carbide clusters, Nb C3 and Nb C6
Publisher: Elsevier BV
Date: 08-2015
Factors influencing the catalytic oxidation of benzyl alcohol using supported phosphine-capped gold nanoparticles
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4CY01168F
Abstract: The nature of Au cluster precursor and activation treatments affect catalyst activity in aerobic benzyl alcohol oxidation.
BFW: A Density Functional for Transition Metal Clusters
Publisher: American Chemical Society (ACS)
Date: 14-03-2007
DOI: 10.1021/JP067752L
Abstract: Ionization potentials (IPs) or electron affinities (EAs) for transition metal clusters are an important property that can be used to identify and differentiate between clusters. Accurate calculation of these values is therefore vital. Previous attempts using a variety of DFT models have correctly predicted trends, but have relied on the use of scaling factors to compare to experimental IPs. In this paper, we introduce a new density functional (BFW) that is explicitly designed to yield accurate, absolute IPs for transition metal clusters. This paper presents the numerical results for a selection of transition metal clusters and their carbides, nitrides, and oxides for which experimental IPs are known. When tested on transition metal clusters, the BFW functional is found to be significantly more accurate than B3LYP and B3PW91.
Kick: Constraining a stochastic search procedure with molecular fragments
Publisher: Wiley
Date: 27-05-2008
DOI: 10.1002/JCC.21026
Abstract: An extension of the Kick program developed by Bera et al. (J Phys Chem A 2006, 110, 4287) is described in which chemically sensible molecular fragments are used in an automated stochastic search algorithm. This results in a vastly reduced region of the potential energy surface which can be explored very quickly. We present use of this modified algorithm to the search for low-lying isomers, and we present candidates for the global energy minimum, for a range of chemical systems. We highlight the usefulness of this procedure for exploring reactions of molecules with transition metal clusters and to the microsolvation of a small dipeptide.
Pt17 nanocluster electrocatalysts: preparation and origin of high oxygen reduction reaction activity
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3NR01152F
Abstract: This work succeeded in fabricating the platinum 17-atom nanocluster-supported carbon black catalyst with high oxygen reduction reaction activity.
Factors Influencing Catalytic Activity of Size-Specific Triphenylphosphine-Ligated Gold Nanoclusters in the Electrocatalytic Hydrogen Evolution Reaction
Publisher: American Chemical Society (ACS)
Date: 22-12-2022
Generation of transient species by laser induced pyrolysis. The high resolution fourier transform infrared spectrum of NCN
Publisher: Elsevier BV
Date: 09-1995
Time-of-flight mass spectrometric detection of mono- and di-substituted benzenes at parts per million concentrations by way of liquid microjet injection and laser ionisation
Publisher: Elsevier BV
Date: 04-2001
Reactions of Nb-2 and Nb-3 with CO, D-2, N-2, and O-2: Reconciling experimental kinetics with density functional theory-calculated reaction profiles
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.
Optical Properties of the Atomically Precise C4 Core [Au9(PPh3)8]3+ Cluster Probed by Transient Absorption Spectroscopy and Time-Dependent Density Functional Theory
Publisher: American Chemical Society (ACS)
Date: 15-01-2021
Reactivity of Oxygen Deficient Cerium Oxide Clusters with Small Gaseous Molecules
Publisher: American Chemical Society (ACS)
Date: 22-05-2015
Abstract: Oxygen deficient cerium oxide cluster ions, Ce(n)O(m)(+) (n = 2-10, m = 1-2n) were prepared in the gas phase by laser ablation of a cerium oxide rod. The reactivity of the cluster ions was investigated using mass spectrometry, finding that oxygen deficient clusters are able to extract oxygen atoms from CO, CO2, NO, N2O, and O2 in the gas phase. The oxygen transfer reaction is explained in terms of the energy balance between the bond dissociation energy of an oxygen containing molecule and the oxygen affinity of the oxygen-deficient cerium oxide clusters, which is supported by DFT calculations. The reverse reaction, i.e., formation of the oxygen deficient cluster ions from the stoichiometric ones was also examined. It was found that intensive heating of the stoichiometric clusters results in formation of oxygen deficient clusters via Ce(n)O(2n)(+) → Ce(n)O(2n-2)(+) + O2, which was found to occur at different temperatures depending on cluster size, n.
Phosphine-stabilised Au9 clusters interacting with titania and silica surfaces: The first evidence for the density of states signature of the support-immobilised cluster
Publisher: AIP Publishing
Date: 02-07-2014
DOI: 10.1063/1.4884642
Abstract: Chemically made, atomically precise phosphine-stabilized clusters Au9(PPh3)8(NO3)3 were deposited on titania and silica from solutions at various concentrations and the s les heated under vacuum to remove the ligands. Metastable induced electron spectroscopy was used to determine the density of states at the surface, and X-ray photoelectron spectroscopy for analysing the composition of the surface. It was found for the Au9 cluster deposited on titania that the ligands react with the titania substrate. Based on analysis using the singular value decomposition algorithm, the series of MIE spectra can be described as a linear combination of 3 base spectra that are assigned to the spectra of the substrate, the phosphine ligands on the substrate, and the Au clusters anchored to titania after removal of the ligands. On silica, the Au clusters show significant agglomeration after heat treatment and no interaction of the ligands with the substrate can be identified.
Regioselective control of the nickel-mediated coupling of acetylene and carbon dioxide – A DFT study
Publisher: Elsevier BV
Date: 08-2008
Threshold Photoionization and Density Functional Theory Studies of the Niobium Carbide Clusters Nb3Cn (n = 1−4) and Nb4Cn (n = 1
Publisher: American Chemical Society (ACS)
Date: 06-2008
DOI: 10.1021/JP800691S
Abstract: We have used photoionization efficiency spectroscopy to determine ionization potentials (IP) of the niobium-carbide clusters, Nb3C(n) (n = 1-4) and Nb4C(n) (n = 1-6). The Nb3C2 and Nb4C4 clusters exhibit the lowest IPs for the two series, respectively. For clusters containing up to four carbon atoms, excellent agreement is found with relative IPs calculated using density functional theory. The lowest energy isomers are mostly consistent with the development of a 2 x 2 x 2 face-centered cubic structure of Nb4C4. However, for Nb3C4 a low-lying isomer containing a molecular C2 unit is assigned to the experimental IP rather than the depleted 2 x 2 x 2 nanocrystal isomer. For Nb4C5 and Nb4C6, interpretation is less straightforward, but results indicate isomers containing molecular C2 units are the lowest in energy, suggesting that carbon-carbon bonding is preferred when the number of carbon atoms exceeds the number of metal atoms. A double IP onset is observed for Nb4C3, which is attributed to ionization from the both the lowest energy singlet state and a meta-stable triplet state. This work further supports the notion that IPs can be used as a reliable validation for the geometries of metal-carbide clusters calculated by theory.
Jet-Cooled Multiphoton Ionization Spectroscopy of the iso-Butanal 3s←n Rydberg Transition
Publisher: Elsevier BV
Date: 03-2001
Effect of Gold Nanoclusters on the Production of Ti3+ Defect Sites in Titanium Dioxide Nanoparticles under Ultraviolet and Soft X-ray Radiation
Publisher: American Chemical Society (ACS)
Date: 31-03-2015
DOI: 10.1021/JP5119162
Laser-Induced Fluorescence of Gaseous Vanadium Methylidyne, VCH: A Triatomic Organometallic Molecule
Publisher: American Chemical Society (ACS)
Date: 02-1995
DOI: 10.1021/JA00112A025
Creation of High‐Performance Heterogeneous Photocatalysts by Controlling Ligand Desorption and Particle Size of Gold Nanocluster
Publisher: Wiley
Date: 07-2021
Abstract: Recently, the creation of new heterogeneous catalysts using the unique electronic/geometric structures of small metal nanoclusters (NCs) has received considerable attention. However, to achieve this, it is extremely important to establish methods to remove the ligands from ligand‐protected metal NCs while preventing the aggregation of metal NCs. In this study, the ligand‐desorption process during calcination was followed for metal‐oxide‐supported 2‐phenylethanethiolate‐protected gold (Au) 25‐atom metal NCs using five experimental techniques. The results clearly demonstrate that the ligand‐desorption process consists of ligand dissociation on the surface of the metal NCs, adsorption of the generated compounds on the support and desorption of the compounds from the support, and the temperatures at which these processes occurred were elucidated. Based on the obtained knowledge, we established a method to form a metal‐oxide layer on the surface of Au NCs while preventing their aggregation, thereby succeeding in creating a water‐splitting photocatalyst with high activity and stability.
Electronic transitions of cobalt carbide, CoC, near 750 nm: A good example of case (bβS ) hyperfine coupling
Publisher: AIP Publishing
Date: 15-11-1995
DOI: 10.1063/1.470148
Abstract: The laser induced fluorescence spectrum of jet-cooled CoC near 750 nm has been measured at high resolution following the reaction of laser-ablated cobalt atoms with methane. The X2Σ+ ground state of CoC is an unusually good ex le of Hund’s case (bβS) coupling. Since Co has a nuclear spin I=7/2, each rotational level is split by the Fermi contact interaction into G=3 and G=4 components, where G=I+S the splitting for N=0 is more than 0.5 cm−1. The X2Σ+ state begins to uncouple toward case (bβJ) with increasing rotation. Transitions to various 2Π excited states occur in the region 13 000–14 500 cm−1 the most prominent of these (for which high resolution spectra have been recorded) lie at 13 079 cm−1 (2Π3/2) and 13 343 cm−1 (2Π1/2). The (bβS) coupling in the ground state produces some unexpected hyperfine intensity patterns, which have been studied in detail. A very low-lying 2Δi state, whose Ω=5/2 and Ω=3/2 components lie at 221 and 1173 cm−1, has been identified. Laser excitation of the 2Π3/2–2Δ5/2 transition has been observed by monitoring the strong 2Π3/2–X2Σ+ emission, which has allowed the 2Δ5/2 state to be characterized at high resolution. A total of 879 rotational-hyperfine transitions between the various 2Π1/2, 2Π3/2, 2Δ5/2, and 2Σ+ states have been assigned and fitted. Matrix elements for a 2Σ+ state in case (bβS) coupling are listed.
Grouping and aggregation of ligand protected Au9 clusters on TiO2 nanosheets
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6RA21419C
Abstract: Au 9 clusters forming groups of clusters on titania nanosheets at least partially consist of in idual clusters both before and after annealing. Au 9 clusters also can attach as in idual clusters.
Molecular Structure of 3-Aminopropyltriethoxysilane Layers Formed on Silanol-Terminated Silicon Surfaces
Publisher: American Chemical Society (ACS)
Date: 07-03-2012
DOI: 10.1021/JP212056S
Spectroscopic observation of gold-dicarbide: Photodetachment and velocity map imaging of the AuC2 anion
Publisher: AIP Publishing
Date: 07-05-2013
DOI: 10.1063/1.4803465
Abstract: Photoelectron spectra following photodetachment of the gold dicarbide anion, ${\\rm AuC}_2^ - $ AuC 2−, have been recorded using the velocity map imaging technique at several excitation wavelengths. The binding energy spectra show well-defined vibrational structure which, with the aid of computational calculations and Franck-Condon simulations, was assigned to a progression in the Au–C stretching mode, ν3. The experimental data indicate that the features in the spectrum correspond to a 2A′ ← 3A′ transition, involving states which we calculate to have bond angles ∼147° but with a low barrier to linearity.
Apparatus for the investigation of high-temperature, high-pressure gas-phase heterogeneous catalytic and photo-catalytic materials.
Publisher: AIP Publishing
Date: 05-2017
DOI: 10.1063/1.4982350
Abstract: A high-temperature, high-pressure, pulsed-gas s ling and detection system has been developed for testing new catalytic and photocatalytic materials for the production of solar fuels. The reactor is fitted with a sapphire window to allow the irradiation of photocatalytic s les from a l or solar simulator light source. The reactor has a volume of only 3.80 ml allowing for the investigation of very small quantities of a catalytic material, down to 1 mg. The stainless steel construction allows the cell to be heated to 350 °C and can withstand pressures up to 27 bar, limited only by the sapphire window. High-pressure s ling is made possible by a computer controlled pulsed valve that delivers precise gas flow, enabling catalytic reactions to be monitored across a wide range of pressures. A residual gas analyser mass spectrometer forms a part of the detection system, which is able to provide a rapid, real-time analysis of the gas composition within the photocatalytic reaction chamber. This apparatus is ideal for investigating a number of industrially relevant reactions including photocatalytic water splitting and CO
Gas phase photocatalytic water splitting of moisture in ambient air: Toward reagent-free hydrogen production
Publisher: Elsevier BV
Date: 10-2020
Far-infrared absorption spectra of synthetically-prepared, ligated metal clusters with Au6, Au8, Au9 and Au6Pd metal cores
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3RA44803G
The interaction of size-selected Ru3 clusters with RF-deposited TiO2: probing Ru–CO binding sites with CO-temperature programmed desorption
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1NA00181G
Abstract: A loss of Ru–CO sites on the clusters suggests encapsulation.
Photoreduction Kinetics of Sodium Tetrachloroaurate under Synchrotron Soft X-ray Exposure
Publisher: American Chemical Society (ACS)
Date: 08-06-2011
DOI: 10.1021/LA200463K
Abstract: We report on the time evolution of the sodium tetrachloroaurate (NaAuCl(4)) chemical properties as a function of soft X-ray exposure in a dried s le on a silicon surface using X-ray photoelectron spectroscopy (XPS). Our investigations provide mechanistic insight into the photoreduction kinetics from Au(III) to Au(I) and then Au(I) to Au(0). We unambiguously show that XPS photoreduction occurs in stepwise fashion via the Au(I) state. Both photoreduction steps undergo first-order kinetics.
Molecular geometries and relative stabilities of titanium oxide and gold-titanium oxide clusters
Publisher: Elsevier BV
Date: 09-2016
Stability of Polymer Interlayer Modified ITO Electrodes for Organic Solar Cells
Publisher: CSIRO Publishing
Date: 2016
DOI: 10.1071/CH15806
Abstract: Indium-tin-oxide (ITO) electrode surfaces were modified using thin polymeric films of ethoxylated polyethylenimine (PEIE) and poly(3,3′-([(9′,9′-dioctyl-9H,9′H-[2,2′-bifluorene]-9,9-diyl)bis(4,1-phenylene)]bis(oxy))bis(N,N-dimethylpropan-1-amine)) (PFPA-1) to investigate the resultant work function and its stability in ambient atmosphere. Both PEIE and PFPA-1 were found to significantly reduce the ITO work function, as a result of a surface dipole at the ITO–polymer interface. After aging for two weeks in ambient air atmosphere, the N-side groups and OH groups in PEIE-modified ITO were found to realign themselves away from the polymer surface, resulting in an orientation more parallel to the surface normal and thus in an increase in work function from 3.5 to 3.8 eV. The work function of PFPA-1-modified ITO was found to increase from 3.65 to 4.1 eV after two weeks of aging in air due to a complete re-orientation of the polar side chains away from the surface, aligning the dipoles more parallel to the surface normal. In both PEIE and PFPA-1 s les, the hydrophobic aliphatic carbon was found to dominate the polymer surface, after aging.
Associative Versus Dissociative Binding of CO to 4d Transistion Metal Trimers: A Density Functional Study
Publisher: Wiley
Date: 04-04-2008
DOI: 10.1002/JCC.20912
Abstract: Density functional calculations were performed to determine equilibrium geometrical structures, transition states and relative energies for M(3) clusters (M = Nb, Mo, Tc, Ru, Rh, Pd, Ag) reacting with CO, leading to proposed reaction pathways. For the Nb(3), Mo(3), and Tc(3) clusters, the lowest energy structure correlates to dissociated CO, with the C and O atoms bound on opposite sides of the metal triangle. For all other trimers, the lowest energy structures maintain the CO moiety. In the case of Pd(3) and Ag(3) the dissociated geometries lie higher in energy than the sum of the separated reactants. In most cases, several multiplicities were found to be similar in energy and for Mo(3)CO and Pd(3)CO singlet-triplet minimum energy crossing points were identified. In the case of Rh(3)CO, minimum energy crossing points for the doublet, quartet, and sextet reaction pathways were determined and compared. The electron densities of pertinent M(3)CO species were investigated using Natural Bond Order calculations. It was found that the effect of the metal trimer on the energy of the pure p-type pi* antibonding orbital of carbon monoxide directly correlates with the occurrence of CO dissociation.
Flow seeding with elemental metal species via an optical method
Publisher: Springer Science and Business Media LLC
Date: 25-05-2012
Onset of carbon–carbon bonding in the Nb5Cy(y = 0–6) clusters: a threshold photo-ionisation and density functional theory study
Publisher: Royal Society of Chemistry (RSC)
Date: 2009
DOI: 10.1039/B813359J
Abstract: We have used photo-ionisation efficiency spectroscopy to determine the ionisation potentials (IPs) of the niobium-carbide clusters, Nb(5)C(y) (y = 0-6). Of these clusters Nb(5)C(2) and Nb(5)C(3) exhibit the lowest IPs. Complementary density functional theory calculations have been performed to locate the lowest energy isomers for each cluster. By comparing the experimental IPs with those calculated for candidate isomers, the structures of the Nb(5)C(y) clusters observed in the experiment are inferred. For all these structures, the underlying Nb(5) cluster has either a "prolate" or "oblate" trigonal bipyramid geometry. Both Nb(5)C(5) and Nb(5)C(6) are shown to contain carbon-carbon bonding in the form of one and two molecular C(2) units, respectively.
Ultraviolet Laser Irradiation of Low Concentration Liquid Microjets: Solute Evaporation and Solvent Initiated Reactivity
Publisher: CSIRO Publishing
Date: 2003
DOI: 10.1071/CH03011
Abstract: Resonance-enhanced 266 nm 1 + 1 multiphoton ionization has been used in conjunction with a liquid microjet time-of-flight mass spectrometer to explore the photochemistry of a 10–3 M solution of anisole in ethanol. Only ions generated in the condensed phase originating from the three-photon non-resonant ionization of the ethanol solvent are liberated into the vacuum. No solute ions generated in solution are observed unless the concentration is increased to 1 M. Under high concentration conditions, solute pairing or aggregation at the liquid surface is a necessary precursor towards liberating solute photoions into the vacuum via a Coulombic explosion. At a solution concentration of 10–3 M, a decreased solute ion density at the liquid surface is insufficient to initiate a Coulombic explosion into the vacuum. Rather, non-resonantly generated solvent ions on the liquid surface dominate the ion ejection process. Related studies on 10–3 M solutions of 4-methoxyphenol in both ethanol and water show that at this concentration solute ionization is most likely to be observed following thermal evaporation from the surface of a liquid beam.
Computational Study of CO Reactivity with Nb3X Heteronuclear Clusters
Publisher: CSIRO Publishing
Date: 2008
DOI: 10.1071/CH08269
Abstract: Density functional calculations were performed to determine the equilibrium structures, ionization potentials, and electron affinities of Nb3X clusters (X = Na, Al, Sc, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd). Pseudo-tetrahedral geometries were preferred for all Nb3X clusters except Nb3Cd. The equilibrium structures and binding energies of the associatively and dissociatively bound products of the Nb3X + CO reaction were calculated at the same level of theory. All clusters were found to thermodynamically dissociate CO. Only Nb3Al and Nb3Cd reduced the enthalpy of dissociation relative to Nb4, whereas all other heteroatoms increased it.
Production of Acrylic Acid through Nickel-Mediated Coupling of Ethylene and Carbon Dioxide—A DFT Study
Publisher: American Chemical Society (ACS)
Date: 27-11-2007
DOI: 10.1021/OM700592W
Using Photoionization Efficiency Spectroscopy and Density Functional Theory to Investigate Charge Transfer Interactions in AuCe3On Clusters
Publisher: American Chemical Society (ACS)
Date: 22-06-2020
The (n, 3s) Rydberg State in Deuterated Aldehydes: Jet-Cooled MPI Spectra of the sym and asym Rotamers of CHD2CHO and CDH2CHO
Publisher: Elsevier BV
Date: 05-1994
Ionization Potentials of Tantalum−Carbide Clusters: An Experimental and Density Functional Theory Study
Publisher: American Chemical Society (ACS)
Date: 16-11-2005
DOI: 10.1021/JP054410R
Abstract: We have used photoionization efficiency spectroscopy to determine the ionization potentials (IP) of the tantalum-carbide clusters, Ta3Cn (n = 1-3) and Ta4Cn (n = 1-4). The ionization potentials follow an overall reduction as the number of carbon atoms increases however, the trend is not steady as expected from a simple electrostatic argument. Instead, an oscillatory behavior is observed such that clusters with an odd number of carbon atoms have higher IPs and clusters with an even number of carbon atoms have lower IPs, with the Ta4C4 cluster exhibiting the lowest IP. Excellent agreement is found with relative IPs calculated using density functional theory for the lowest energy structures, which are consistent with the development of a 2 x 2 x 2 face-centered nanocrystal. This work shows that IPs may be used as a reliable validation for the geometries of metal-carbide clusters calculated by theory. The variation in IP can also be interpreted qualitatively with application of a simple model based upon isolobal frontier orbitals.
The (n, 3s) Rydberg State in Deuterated Aldehydes: Jet-Cooled MPI Spectra of the Propanal Isotopomeric Series
Publisher: Elsevier BV
Date: 05-1994
Near threshold photochemistry of propanal. Barrier height, transition state structure, and product state distributions for the HCO channel
Publisher: American Chemical Society (ACS)
Date: 25-05-2002
DOI: 10.1021/JP025590X
Rotational Energy Distributions of Benzene Liberated from Aqueous Liquid Microjets: A Comparison between Evaporation and Infrared Desorption
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/CH05319
Abstract: We have measured the rotational energy distribution of benzene molecules both evaporated and desorbed by an IR laser from a liquid microjet. Analysis of the 601 vibronic band of benzene has shown that the benzene molecules evaporating from the liquid microjet surface have a rotational temperature of 157 ± 7 K. In contrast, the rotational temperature of benzene molecules desorbed from the liquid microjet by a 1.9 μm laser pulse is 82 ± 5 K. However, in both cases careful inspection of the spectral profiles shows that the experimental rotational distributions are non-Boltzmann, displaying an underpopulation of high rotational states and a relative overpopulation of the low rotational states. The non-equilibrium evaporation and desorption spectral profiles are consistent with a model that involves transfer of internal energy into translation upon liberation from the condensed phase.
Innentitelbild: Creation of High‐Performance Heterogeneous Photocatalysts by Controlling Ligand Desorption and Particle Size of Gold Nanocluster (Angew. Chem. 39/2021)
Publisher: Wiley
Date: 12-07-2021
A Systematic Density Functional Theory Study of the Complete De-ligation of Ru3(CO)12
Publisher: Wiley
Date: 05-2016
Excited states of Nb3N2 and Nb3C2: Density functional theory, CASSCF, and MRCI studies
Publisher: AIP Publishing
Date: 27-04-2009
DOI: 10.1063/1.3122542
Abstract: Complete active space self-consistent field (CASSCF) and multireference configuration interaction (MRCI) methods are used to investigate the Nb3N2 and Nb3C2 clusters in order to determine the agreement between multireference methods, density functional theory (DFT), and experiment. These two clusters are ideal candidates to study as the known spectroscopy can serve to validate the computational results, yet there is still room for the calculations to inform further spectroscopic experiments. We find that the MRCI leading configuration for each of the ground states is in agreement with that predicted by DFT but only accounts for up to 70% of the total configuration. CASSCF and DFT geometries are also in general agreement. Transition energies between the neutral and cationic manifolds are found to be poorly predicted by MRCI relative to the computationally cheap DFT method. For Nb3C2 we find that a higher energy isomer may have an electronic transition in the spectral vicinity as the lowest energy isomer.
Insights into the Oxidant/Polymer Interfacial Growth of Vapor Phase Polymerized PEDOT Thin Films
Publisher: Wiley
Date: 25-06-2018
Life cycle indicator comparison of copper, silver, zinc and aluminum nanoparticle production through electric arc evaporation or chemical reduction
Publisher: Springer Science and Business Media LLC
Date: 05-2015
The lowest-lying excited singlet and triplet electronic states of propanal: an ab initio molecular orbital investigation of the potential energy surfaces
Publisher: Royal Society of Chemistry (RSC)
Date: 2004
DOI: 10.1039/B313777E
Effect of Charge and Phosphine Ligands on the Electronic Structure of the Au8 Cluster
Publisher: American Chemical Society (ACS)
Date: 24-05-2019
The near infrared electronic spectrum of tungsten methylidyne, WCH
Publisher: AIP Publishing
Date: 15-10-1996
DOI: 10.1063/1.472502
Abstract: The laser excitation spectrum of tungsten methylidyne, WCH, has been recorded in the 12 000–15 400 cm−1 region. A total of 14 vibronic bands of WCH and 16 bands of WCD have been observed in this region. Rotational analysis shows that the ground state is X̃3/2(2Δ), with the substitution structure r0(W≡C)=1.73665 Å and r0(C–H)=1.0765 Å. The excited vibronic levels have been assigned, on the basis of their WCH/WCD isotope shifts and their wavelength resolved fluorescence patterns, to three electronic states, Ã3/2(2Δ), B̃1/2(2Π), and C̃5/2(2Φ), at 12 090, 13 392, and 14 110 cm−1, respectively. The wavelength resolved fluorescence spectra have also established the low-lying vibrational levels of the ground state. The ground state bending fundamental lies at 660 cm−1, while the W–C stretching frequency is 1006 cm−1 the corresponding frequencies in WCD are 501 cm−1 and 953 cm−1, respectively. No evidence for the C–H stretching frequency has been found. Emission has also been observed to a low-lying electronic state, 813 cm−1 above the X̃3/2 state. The pattern of rotationally resolved emission to this state clearly indicates that it is a 4Σ1/2 state. Its bending frequency is 612 cm−1, and its W–C stretching frequency is 971 cm−1, indicating a slightly longer bond length than in the X̃3/2 state. High resolution cw laser spectra of the (0,0) bands of the two lowest excited electronic states [Ã3/2(2Δ) and B̃1/2(2Π)] reveal a small splitting of the four principal tungsten isotopes (182W, 183W, 184W, and 186W) which serves to confirm the presence of tungsten in the carrier. Hyperfine splitting associated with the 183W nucleus (I=1/2) has been observed for the (0,0) band of the Ã3/2−X̃3/2 system, allowing the electron configuration of the ground state to be elucidated.
Mapping‐Out Catalytic Processes in a Metal–Organic Framework with Single‐Crystal X‐ray Crystallography
Publisher: Wiley
Date: 03-02-2017
Abstract: Single-crystal X-ray crystallography is employed to characterize the reaction species of a full catalytic carbonylation cycle within a Mn
First spectroscopic observation of gold(i ) butadiynylide: Photodetachment velocity map imaging of the AuC4H anion
Publisher: AIP Publishing
Date: 28-07-2016
DOI: 10.1063/1.4959130
Abstract: The velocity map imaging technique was used in the investigation of gold(i) butadiynylide, AuC4H−, with images recorded at two excitation wavelengths. The resultant photodetachment spectra show a well defined vibrational progression in the neutral with an energy spacing of 343 ± 3 cm−1. The adiabatic electron affinity was determined to be 1.775 ± 0.005 eV and assigned to the X1Σ+←X2Σ+ transition between the anionic and neutral ground states. Franck-Condon simulations performed on density functional theory optimized geometries assisted the assignment of linear geometries to the neutral and anion and the observed vibrational progression to that of the Au–C4H stretch.
Photodissociation dynamics of the reaction CF2Br2+hν→CF2+ 2Br. Energetics, threshold and nascent CF2 energy distributions for λ=223–260 nm
Publisher: Royal Society of Chemistry (RSC)
Date: 2000
DOI: 10.1039/B000203H
HCO (N,Ka,Kc,J) distributions from near-threshold photolysis of H2CO (J,Ka,Kc)
Publisher: AIP Publishing
Date: 22-02-1998
DOI: 10.1063/1.475736
Abstract: The dynamics of the reaction H2CO+hν(λ≈330 nm)→H+HCO have been studied following excitation of formaldehyde into the Ã(1A2) state, just above the dissociation threshold of the X̃(1A1) state. Formaldehyde was excited via specific J, Ka, Kc rotational states and the ensuing rotational distribution of HCO measured by fully resolving N, Ka, Kc, and J=N±S of the fragment. When only the N and Ka quantum numbers of both formaldehyde and the formyl radical are considered, the distributions are generally modeled well by phase space theory (PST). Within ≈10 cm−1 of the threshold, however, the PST predictions consistently exceed the experimental populations. This was accounted for by the inclusion of a centrifugal barrier in the PST model. The attractive part of the effective centrifugal potential was modeled by a dipole-induced dipole plus dispersion interaction. The barrier is weak and long range (& Å). Resolution of Kc in the reaction, in both parent and product, gave large deviations from the PST model. The HCO population distributions separate according to whether Kc was the upper- or lower-energy state. Additionally, the upper/lower preference was sensitive to the choice of Kc in the parent. Insufficient data are currently available to quantify this observation. The product state distribution was also found to be independent of the spin–rotation state of HCO.
Suppression of phosphine-protected Au9 cluster agglomeration on SrTiO3 particles using a chromium hydroxide layer
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D1MA01226F
Abstract: Chromium hydroxide overlayer have been shown to have great potential to protects the phosphine-ligated Au clusters from agglomeration after the removal of the ligands and under conditions of photocatalytic water splitting.
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Amount: $560,000.00
Funder: Australian Research Council
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