MILLIMETER, SUBMILLIMETER AND INFRARED-SPECTRA OF DISULPHANE (HSSH) AND ITS ISOTOPIC-SPECIES

Spectroscopic work on HSSH over the last 20 years is summarized. High-resolution spectroscopic measurements of both the rotational and torsional spectra are discussed. The rotational spectra of the lower K(a) sub-bands are dominated by the effects of centrifugal distortion-induced K-type doubling. A simultaneous analysis of the rotational spectrum and the torsion-rotational spectrum near 417 cm-1 resulted in the determination of the barrier heights to internal rotation, viz., V(cis) = 2843 cm-1 and V(trans) = 2037 cm-1. For the first time a reliable, complete molecular structure has been determined based on millimetre wave and infrared data. The structural parameters are r(SS) = 2.0564 angstrom, r(SH) = 1.3421 angstrom, dihedral angle gamma = 90.34-degrees and angle-(SSH) = 97.88-degrees.