AB inttio study of the rotational isomlrism, vibrational force field and frequencies of vinyl mercaptan

Abstract

The general harmonic force fields of the syn, gauche and anti rotamers and the internal rotation in vinyl mercaptan have been studied using STO/4.31 G orbitals. The syn and gauche rotamers are found to be stable with the syn rotamer 1.9 kJ mol −1 lower in energy. The computed vibrational frequencies of the three rotamers are very similar and higher than the observed infra red frequencies. A one dimensional treatment of the internal rotation shows this vibration to be very anharmonic for the gauche retainer.