ORCID Profile
0000-0002-9028-5737
Current Organisations
The University of Queensland School of Mathematics and Physics
,
University of Sydney
,
University of Queensland Australian Institute for Bioengineering and Nanotechnology
,
Flinders University
,
Universität Ulm
,
Osaka University
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Publisher: American Physical Society (APS)
Date: 12-04-2013
Publisher: The Vacuum Society of Japan
Date: 2007
DOI: 10.3131/JVSJ.50.437
Publisher: Elsevier BV
Date: 10-2008
Publisher: Wiley
Date: 06-03-2020
Publisher: American Chemical Society (ACS)
Date: 21-11-2014
DOI: 10.1021/JP5093898
Publisher: Elsevier BV
Date: 02-2015
Publisher: Elsevier BV
Date: 03-2013
Publisher: IOP Publishing
Date: 18-10-2007
Publisher: Elsevier BV
Date: 2007
Publisher: Elsevier BV
Date: 10-2016
Publisher: Elsevier BV
Date: 05-2009
Publisher: IOP Publishing
Date: 24-09-2009
Publisher: American Chemical Society (ACS)
Date: 20-06-2016
Publisher: Springer Science and Business Media LLC
Date: 21-02-2006
Publisher: American Chemical Society (ACS)
Date: 24-05-2019
Publisher: IOP Publishing
Date: 20-11-2004
Publisher: American Chemical Society (ACS)
Date: 10-06-2022
Publisher: The Royal Society
Date: 10-2016
Abstract: The adsorption of water on bimetallic PtRu/Pt(111) surface alloys has been studied based on periodic density functional theory calculations including dispersion corrections. The Ru atoms of the PtRu surface alloy interact more strongly with water than Pt atoms, as far as both single water molecules and ice-like hexagonal structures are concerned. Within the surface alloy layer, the lateral ligand effect reducing the local reactivity of the surface atoms with increasing Ru content is more dominant than the opposing geometric effect due to the tensile strain. The structural preference for the Ru atoms also prevails at room temperature, as ab initio molecular dynamics simulations show.
Publisher: The Vacuum Society of Japan
Date: 2005
DOI: 10.3131/JVSJ.48.235
Publisher: The Vacuum Society of Japan
Date: 2006
DOI: 10.3131/JVSJ.49.433
Publisher: IOP Publishing
Date: 08-03-2006
DOI: 10.1143/JJAP.45.1765
Publisher: American Chemical Society (ACS)
Date: 15-07-2021
Publisher: The Vacuum Society of Japan
Date: 2006
DOI: 10.3131/JVSJ.49.440
Publisher: IOP Publishing
Date: 05-11-2009
DOI: 10.1088/0953-8984/21/47/474219
Abstract: We review the physical mechanisms that lead toward the conversion of graphene into its fully hydrogenated counterpart, which is a material that possesses properties closer to those of diamond than graphene. These are discussed from a theoretical perspective, i.e., from calculations based on density functional theory. We first discuss stability trends in small clusters of adsorbed hydrogen, as well as surface structure and concurrent reactivity changes for graphene one-face and two-face hydrogenation. Effects of adsorbed hydrogen on graphene electronic states, which are essential to adsorbed hydrogen structure discrimination, are also discussed.
Publisher: Royal Society of Chemistry (RSC)
Date: 2008
DOI: 10.1039/B806186F
Abstract: The behavior of hydrogen near a platinum-surface-adsorbed carbon monoxide molecule is described using a potential energy term constructed from density functional theory. A clear nonattractive interaction of hydrogen with CO is confirmed, most notably with oxygen, which retains its strong H-repulsive traits in the Pt-bound CO case. Inhibiting effects of CO greater than what is expected from simple adsorption site exclusion are discussed with regard to adsorption/desorption and mobility on platinum, as well as possibilities of COH and HCO formation.
Publisher: IOP Publishing
Date: 24-08-0031
Publisher: Physical Society of Japan
Date: 15-11-1970
Publisher: Elsevier BV
Date: 06-2006
Publisher: Physical Society of Japan
Date: 15-03-2009
Publisher: IOP Publishing
Date: 24-08-2007
DOI: 10.1088/0953-8984/19/36/365210
Abstract: We have developed and proposed a model for reactive ion etching (RIE) process design of nickel oxide thin films using a computational materials design based on ab initio calculations. On etching NiO, we found that it was necessary to have hydrogen-based reactive gases in the initial state in order to enhance RIE (e.g. NH(3), CH(4)). We strongly suggest the use of CH(4) or any H-based gas source other than CHF(3) to enhance RIE process.
Publisher: Elsevier BV
Date: 06-2011
Publisher: Elsevier BV
Date: 2015
Publisher: The Vacuum Society of Japan
Date: 2005
DOI: 10.3131/JVSJ.48.205
Publisher: American Physical Society (APS)
Date: 26-03-2007
Publisher: Beilstein Institut
Date: 10-02-2014
DOI: 10.3762/BJNANO.5.15
Abstract: The properties of a halogen-covered platinum(111) surface have been studied by using density functional theory (DFT), because halides are often present at electrochemical electrode/electrolyte interfaces. We focused in particular on the halogen-induced work function change as a function of the coverage of fluorine, chlorine, bromine and iodine. For electronegative adsorbates, an adsorption-induced increase of the work function is usually expected, yet we find a decrease of the work function for Cl, Br and I, which is most prominent at a coverage of approximately 0.25 ML. This coverage-dependent behavior can be explained by assuming a combination of charge transfer and polarization effects on the adsorbate layer. The results are contrasted to the adsorption of fluorine on calcium, a system in which a decrease in the work function is also observed despite a large charge transfer to the halogen adatom.
Publisher: IOP Publishing
Date: 22-08-2008
DOI: 10.1143/JJAP.47.6931
Publisher: Elsevier BV
Date: 11-2004
Publisher: Elsevier BV
Date: 09-2006
Publisher: IOP Publishing
Date: 02-2005
DOI: 10.1143/JJAP.44.882
Abstract: We investigate the electronic and magnetic properties of single-walled carbon nanotubes (SWNTs) filled with Fe nanowires, based on the spin-polarized density functional theory. We find that in the stable structure, the Fe-filled (3,3) and (5,0) SWNTs exhibit semiconducting properties, and the magnetic moment of Fe nanowires inside disappears. On the other hand, the Fe-filled (4,4), (5,5), (6,6) and (6,0) SWNTs, having larger radii, are metallic and exhibit ferromagnetic properties. The corresponding magnetic moment increases with increasing nanotube diameter.
Publisher: Springer Science and Business Media LLC
Date: 27-10-2020
DOI: 10.1038/S41524-020-00432-1
Abstract: The use of solid-state electrolytes to provide safer, next-generation rechargeable batteries is becoming more feasible as materials with greater stability and higher ionic diffusion coefficients are designed. However, accurate determination of diffusion coefficients in solids is problematic and reliable calculations are highly sought-after to understand how their structure can be modified to improve their performance. In this paper we compare diffusion coefficients calculated using nonequilibrium and equilibrium ab initio molecular dynamics simulations for highly diffusive solid-state electrolytes, to demonstrate the accuracy that can be obtained. Moreover, we show that ab initio nonequilibrium molecular dynamics can be used to determine diffusion coefficients when the diffusion is too slow for it to be feasible to obtain them using ab initio equilibrium simulations. Thereby, using ab initio nonequilibrium molecular dynamics simulations we are able to obtain accurate estimates of the diffusion coefficients of Li ions in Li 6 PS 5 Cl and Li 5 PS 4 Cl 2 , two promising electrolytes for all-solid-state batteries. Furthermore, these calculations show that the diffusion coefficient of lithium ions in Li 5 PS 4 Cl 2 is higher than many other potential all-solid-state electrolytes, making it promising for future technologies. The reasons for variation in conductivities determined using computational and experimental methods are discussed. It is demonstrated that small degrees of disorder and vacancies can result in orders of magnitude differences in diffusivities of Li ions in Li 6 PS 5 Cl, and these factors are likely to contribute to inconsistencies observed in experimentally reported values. Notably, the introduction of Li-vacancies and disorder can enhance the ionic conductivity of Li 6 PS 5 Cl.
Publisher: AIP Publishing
Date: 15-06-2007
DOI: 10.1063/1.2749295
Abstract: We calculate the adiabatic potential energy for hydrogen atom motion on a Pd(111) surface and in a subsurface within the framework of the density functional theory in order to understand the diffusion mechanism of a hydrogen atom from the Pd(111) surface to the subsurface. According to the calculated adiabatic potential energy surface for the hydrogen atom motion up to the third atom layer, an effective diffusion path of the hydrogen atom into the Pd bulk starts from the fcc hollow site on the Pd(111) surface. Moreover, the diffusion path passes through the octahedral site between the first and the second Pd atom layers, the tetrahedral site beneath a Pd atom of the first layer or above the Pd atom of the third layer, and the octahedral site between the second and third layer.
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4CP00237G
Abstract: In this study, we provide a complete picture of how adatoms can reduce the work function of a metal surface by contrasting two independent mechanisms.
Publisher: IOP Publishing
Date: 09-01-2006
Publisher: Elsevier BV
Date: 08-2014
Publisher: IOP Publishing
Date: 08-2008
Publisher: Elsevier BV
Date: 08-2013
Publisher: Surface Science Society Japan
Date: 2006
Publisher: The Electrochemical Society
Date: 2014
DOI: 10.1149/2.003408JES
Publisher: Physical Society of Japan
Date: 15-02-2005
DOI: 10.1143/JPSJ.74.742
Location: Australia
Location: Australia
No related grants have been discovered for Tanglaw Roman.