Relativistic tight-binding model: Application to Pt surfaces

Abstract

We report a parametrization of a previous self consistent tight binding model, suitable for metals with high atomic number in which nonscalar relativistic effects are significant in the electron physics of condensed phases. The method is applied to platinum. The model is fitted to DFT band structures and cohesive energies and spectroscopic data on platinum atoms in 5 oxidation states and is then shown without further parametrization to correctly reproduce several low index surface structures. We also predict reconstructions of some vicinal surfaces.

Influence of Adsorbates on the Electronic Structure, Bond Strain, and Thermal Properties of an Alumina-Supported Pt Catalyst

“…Since the typical values of W obtained here (Table ) are a small fraction of typical cohesive energies ( e.g. , the cohesive energy of Pt is ∼5.8 kJ/mol), − the effect of the adsorbate-induced stress is only weakly related to the elastic constants associated with nonsurface atoms. For this reason, the Einstein temperatures and frequencies for both adsorbates (H and CO) and all partial pressures studied in this work are set to the value derived for the zero coverage case .…”

Coherent x-ray scattering experiments of Pt(001) surface dynamics near a roughening transition

“…The fit value for K. This value is close to the average theoretical value of 1.35 eV. 19 The value for the non-universal constant A is 0.6(2) K. This indicates that the free energy is 90 % of 0 f for the temperatures tens of degrees below T R, (most temperature range) and appreciably different from it only when the temperature is as close to T R as ~20 K.…”

Self consistent tight binding model for dissociable water

“…We have since used it to describe magnetic materials 12 and metals. 7,8 SCTB is similar to the approach of Refs. 13-15 but differs from it in some details which are important in our applications.…”

“…The code has been used previously and subsequently to generate parameter sets for titanium dioxide, 6 titanium metal, 7 ruthenium dioxide, 9 and platinum metal. 8 The data set which was used for fitting parameters for water included first principles energies for 364 configurations of the water molecule, 1304 atomic configurations of the water dimer (using MP2/6-311+g(3df,2p)) and all the harmonic frequencies of the relaxed water trimer (using MP2/aug-cc-pVDZ and reducing the computed frequencies by a factor 0.95 in the fitting database). The 364 water configurations were the equilibrium structure (O-H = 0.95720 Å and H-O-H = 104.3758 • ) and 363 monomers generated in O-H 1 and O-H 2 bond ranges from 0.7 to 1.3 Å with step 0.06 Å at scissor angles 100 • , 103.3 • , and 106.67 • .…”

“…In the initial stages we introduce a finite "temperature" in the Monte Carlo algorithm to let the process get out of local minima in the error function and then lower the temperature for final adjustment. The fitting algorithms have been incorporated in a general "fitting code" which can use first principles cluster data (as in the application in this paper) or first principles data on cohesive energies and band structures of bulk solids (as was used for oxides 6 and metals 7,8 previously). The authors will make this and the direct dynamics SCTB code available on request.…”