Potential Barrier and Molecular Structure of Methyl Mercaptan from its Microwave Spectra

The microwave spectrum of normal methyl mercaptan has been studied in the frequency range from 14 to 29 kMc/sec. The potential barrier height hindering internal rotation has been determined as 444±10 cm -1 from the analysis of the lines corresponding to the transitions involving both over-all and internal rotations. The fine structures of J =1←0, K =0←0 lines of the various isotopic species have also been analysed and discussed. The molecular structure of methyl mercaptan has been calculated to be d SH =1.336±0.01 A, d CS =1.819±0.005 A, d C H =1.091±0.01 A, \(∠\)CSH=96°30'±1°, \(∠\)HCH=109°45'±30' and the angle between CS bond and methyl axis, θ=2^°0'±30'.