Effect of temperature on the hydrogen bond νs band. Part 2.—Theory
Abstract
The proposed origin for the temperature sensitivity of the νs band of hydrogen bonded systems in terms of anharmonic coupling with intermolecular modes has been examined by calculations employing the Stepanov separation of the low and high frequency modes. If only transitions within 50 cm–1 of the band origin contribute, the temperature coefficient is very small. If all sub-bands contribute, positive coefficients are obtained, the most significant factor being the change in the strength of the hydrogen bond in the upper νs state.