Matrix effects on hydroxy-group vibrational frequencies caused by weak intermolecular interactions

Abstract

Matrix effects on the frequencies of i.r. vibrations of hydroxy and deuteroxy groups in CH₃OH and D₂O have been studied. Band shifts, Δν, show a linear dependence on √T_c(where T_c is the critical temperature) of the substance comprising the matrix, as a measure of the intermolecular potential. Within a homologous series Δν is more sensitive to hydrogen bonding than to van der Waals interactions. This implies that the application of the Badger–Bauer rule to hydrogen-bonded systems must take non-polar solvents as frequency standard and not the vapour state.

The bending mode of D₂O shows different changes: it has a red-shifted matrix effect and is blue-shifted by hydrogen bonds.