Vapor Phase Raman Transitions in the CH2 Scissoring Region and the Ring Puckering Vibration of Trimethylene Oxide and some Deuterated Analogs

Abstract

The vapor phase Raman spectra of trimethylene oxide (TMO) and two of its deuterated analogs (α-d2 and β-d2) each show one sharp line on a weak, broad, and unresolved band in the CH2 scissoring region. Under high resolution these lines are resolved into several components. They are assigned to the fundamentals of the scissoring mode of α-CH2 (in-phase, A1 symmetry, in the case of the normal and β-d2 compound) and overlapping bands resulting from interaction with the low frequency puckering vibration. The agreement between Raman and i.r. data is excellent and the assignments are entirely consistent. Raman lines corresponding to the out-of-phase combination (B2 symmetry) of the α-CH2 scissoring vibration and the scissoring mode of the β-CH2 group (in normal, α-d2 and α,α′-d4 TMO) cannot be resolved.