Knowledge Bank

The rotational spectrum of methyl hydrodisulfide is typical of a rigid asymmetric top in contrast to the microwave spectrum of methyl hydroperoxide. Transitions for all three dipole selection rules were assigned and measured. The internal rotation barriers for the SH group are high as shown by the absence of splittings and shifts due to non-rigidity. This fact is further supported by ab initio calculations of selected conformations. The internal rotation of the methyl group give rise to small splittings of the rotational transitions with higher J. The analysis of the rotational spectrum of methyl deuterodisulfide provided a reliable value of $88\circ$ for the CSSH dihedral angle.