Complexes of small neutral gold clusters and hydrogen sulphide: A theoretical study

Binding energies, geometries, charge transfers and vibrational frequencies of complexes of neutral gold clusters Aun (n = 1–4) and H2S are computed using density functional theory. The geometries of Aun and H2S are little changed upon complex formation but, for the Au4SH2 complex, one of the two low-lying Au4 isomers is more stabilized by H2S due to intracomplex hydrogen bonding and may be the lowest-energy Au4SH2 structure. For the complexes, computed infrared and Raman spectra are discussed with a focus on distinguishing between the two candidates for the lowest-energy Au4SH2 structure.