Infrared spectra of HSCS+, c-HSCS, and HCS2− produced on electron bombardment of CS2 in solid para-hydrogen
We report infrared (IR) spectra of HSCS+, c-HSCS, HCS2−, and other species produced on electron bombardment of a mixture of CS2 and para-hydrogen (p-H2) during deposition at 3.2 K. After maintenance of the deposited matrix in darkness for 12 h, the intensities of the absorption lines of HSCS+ at 2477.2 (ν1), 1525.6 (ν2), and 919.6 cm−1 (ν3) decreased through neutralization of HSCS+ with trapped electrons. During this period, the intensities of the lines of HCS2− at 2875.7 (ν1), 1249.9 (ν5), 1003.2 (ν6), and 814.3 cm−1 (ν4) increased due to reaction between H and CS2−. The intensities of the lines observed at 2312.7 and 889.0 cm−1, which are assigned to the c-HSCS radical, increased after maintenance in darkness and greatly diminished after irradiation at 373 nm. The IR spectra of HSCS+, HCS2−, and c-HSCS are reported for the first time. The IR absorption lines of the t-HSCS radical, t-HC(S)SH, and c-HC(S)SH were also identified; their wavenumbers are similar to those reported for these species in an Ar matrix. The corresponding spectra of the 13C, 34S, and D isotopic variants of these species were observed. The assignments were made according to the expected chemical behavior, predicted potential energies of associated reactions, and a comparison of observed and predicted wavenumbers and their 13C, 34S, and D isotopic ratios. In contrast to the observed significant red shifts of the OH-stretching wavenumbers of HOCO+ and HOCS+ in solid p-H2 compared to those in the gaseous phase due to proton sharing with H2, the wavenumber of the HS-stretching mode of HSCS+ in solid p-H2 (2477.2 cm−1) is similar to the anharmonic wavenumber of HSCS+ (2424 cm−1) predicted with the B3LYP/aug-cc-pVTZ method, indicating that the sharing of a proton between HSCS+ and neighboring H2 molecules is insignificant.