Conformational analysis, barriers to internal rotation, vibrational assignment, and ab initio calculations of 1,2-difluoroethane

Abstract

The far infrared (50-370-cm -1 ) and low frequency Raman (70-300-cm -1 ) spectra of gaseous 1,2-difluoroethane have been recorded. The fundamental asymmetric torsional frequencies of the more stable gauche (two fluorine atoms oriented gauche to one another) and the high energy trans conformations have been observed in the far infrared spectrum of the gas at 147.0 and 116.7 cm -1 , respectively. For the trans conformer, four Q-branches arising from transitions between excited torsional vibrational states have also been observed