Vibrational states for hydrogen in palladium

Abstract

Vibrational potentials for hydrogen isotopes in PdH and Pd4H are determined from first-principles total-energy calculations.

Nanoscale hydride formation at dislocations in palladium:Ab initiotheory and inelastic neutron scattering measurements

“…The latter scaling corresponds to a needed softening of the DFT calculations of vibrational spectra for H in Pd compared with experimental measurements; the overestimation of vibrational excitation is independent of exchange-correlation potential and treatment of H and Pd ionic cores 14 and is consistent with earlier fully-anharmonic calculations of isolated hydrogen in Pd. 15 The experimentally measured line shape is in good agreement with the prediction of scattering at room temperature, but the shapes begin to deviate as temperature is lowered.…”

Absorption and diffusion of hydrogen in palladium-silver alloys by density functional theory

“…39 This was also concluded by Elsässer et al 43 Table IV shows that the calculated results are in good agreement with the experiment 38 and the previous calculations. 6 For H in PdH 0.25 , the energies calculated by Elsässer et al overestimate the energies to some extent. Elsässer et al explained this by lack of the local lattice relaxations during the PES calculations.…”

“…This does not seem important for the energies if we compare our results with the experiment, indicating that the total-energy calculations are good enough to predict the vibrational energies. To explain inelastic-neutron-scattering spectra, 43 Elsässer et al 6 proposed that two excited states of 137Ϯ2 meV and 156 Ϯ3 meV seem to be the excitations e 200 (1) and e 200 (2) , respectively. These states are also observed in our calculations.…”

“…Over the years, there has been a continued theoretical interest in the vibrational energies, the diffusion, and the dissociation of H in pure Pd, [6][7][8][9][10][11][12][13][14][15] but there is little theoretical understanding of H in Pd-Ag alloys. This paper and a recent paper by Lo "vvik 16 intend to fill this gap.…”

First-principles investigations of isotope effects in thermodynamic properties of TiX2 (X=H, D, and T) system

“…Due to their importance a large number of investigations have been performed with such thermal vibrations in solids including semiconductors [1][2][3][4][5], metal hydrides [6][7][8][9][10][11][12][13][14], and other compounds [15,16]. Generally, we can use the concept of phonon to describe thermal vibrations and to determine thermal properties in crystals and in particular their specific heat, thermal expansion coefficients and so on.…”