REACTION OF ATOMIC-HYDROGEN AND CARBON-DISULFIDE - INFRARED-SPECTRA OF HSCS AND HSHCS IN SOLID ARGON

Matrix infrared spectroscopy has been used to characterize the cocondensation reaction products of H atoms and CS2 in solid argon at 12 K. The major product bands at 1275.2 and 1227.8 cm-1 were characterized by photolysis with 320-1000-nm radiation and reappearance on annealing to 18 K to allow diffusion and reaction of trapped H atoms. Deuterium, C-13, and S-34 isotopic data were used to identify the major product as the HSCS radical. Vibrational frequencies calculated at the DZP level for the trans conformer are in excellent agreement with the observed spectrum. A most striking feature in the spectrum is the intensification of the 2-nu(c-s) mode due to Fermi resonance with the nu(c = s) fundamental. Minor product bands at 1082 and 1059 cm-1 increased on 320-1000-nm photolysis, disappeared on 220-1000-nm irradiation, and did not reappear on final sample annealing. DZP calculations support assignment of these bands to cis- and trans-dithioformic acid, respectively.