The intramolecular potential of water molecules engaged in hydrogen bonding from analysis of the overtone spectrum of ice I

Abstract

An analysis of the fundamental and overtone spectra of ice Ih is presented. It is shown that the major features of the spectra of H2O, D2O, and H2O/D2O mixtures can be modeled by a theory which asserts that there is no change in the anharmonic diagonal stretching terms in the intramolecular potential upon hydrogen bonding. The changes in the anharmonic constant arise from the change in the OH stretching amplitude. Both the harmonic and anharmonic terms can be expressed in terms of a hydrogen bond parameter η which can be extracted from the observed OH stretching frequency alone. The influence of intermolecular coupling in dimers and pure crystals gives rise to new spectral features which can be assigned using the model.