Vibrational study in neon matrix of H2S-H2O, H2S-(H2O)2, and (H2S)2-H2O complexes. Identification of the two isomers: HOH-SH2 (H2O proton donor) and HSH-OH2 (H2S proton donor).

For the first time, the investigation of water molecules complexed with hydrogen sulfide in solid neon was performed from 80 to 6000 cm-1 using Fourier transform infrared spectroscopy. In the first step, we identify the ν1 and ν3 frequencies of the proton donor in the H2S dimer. From concentration effects and with the help of theoretical results, we have highlighted the presence of the two stable isomers, HOH-SH2 where H2O is the proton donor and HSH-OH2 where H2S is the proton donor. We also identify several transitions for (H2S)2-H2O and H2S-(H2O)2 complexes, the first step of the microsolvation of H2S, and we propose structures for these complexes with the help of theoretical calculations at the second-order Møller-Plesset level.