TY  - JOUR
A1  - Melani, Giacomo
A1  - Nagata, Yuki
A1  - Campen, Richard Kramer
A1  - Saalfrank, Peter
T1  - Vibrational spectra of dissociatively adsorbed D2O on Al-terminated alpha-Al2O3(0001) surfaces from ab initio molecular dynamics
T2  - The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr
N2  - Water can adsorb molecularly or dissociatively onto different sites of metal oxide surfaces. These adsorption sites can be disentangled using surface-sensitive vibrational spectroscopy. Here, we model Vibrational Sum Frequency (VSF) spectra for various forms of dissociated, deuterated water on a reconstructed, Al-terminated α-Al2O3(0001) surface at submonolayer coverages (the so-called 1-2, 1-4, and 1-4′ modes). Using an efficient scheme based on velocity-velocity autocorrelation functions, we go beyond previous normal mode analyses by including anharmonicity, mode coupling, and thermal surface motion in the framework of ab initio molecular dynamics. In this way, we calculate vibrational density of states curves, infrared, and VSF spectra. Comparing computed VSF spectra with measured ones, we find that relative frequencies of resonances are in quite good agreement and linewidths are reasonably well represented, while VSF intensities coincide not well. We argue that intensities are sensitively affected by local interactions and thermal fluctuations, even at such low coverage, while absolute peak positions strongly depend on the choice of the electronic structure method and on the appropriate inclusion of anharmonicity.
Y1  - 2019
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/48981
SN  - 0021-9606
SN  - 1089-7690
VL  - 150
IS  - 24
PB  - American Institute of Physics
CY  - Melville
ER  -