The influence of pressure on the infrared spectra of hydrogen-bonded solids. I. Compounds with O-H - - - O bonds

Abstract

Measurements have been made of the influence of pressures up to 40 kbar on the hydrogen-bonded OH stretching and bending frequencies of a series of solids whose hydrogen bonds cover the full range of strengths from very weak to very strong. The bending frequencies all increase with increasing pressure, and the stretching frequencies nearly all decrease. The exceptions to this general pattern are shown by compounds with strong, symmetrical, hydrogen bonds, whose stretching frequencies increase with increasing pressure. This reversal of behaviour is consistent with the predictions of a simple model based on Lippincott and Schroeder's empirical potential energy function for hydrogen bonds.