An ab initio study of the effect of hydration on the vibrational spectrum of hydrogen sulfate

Abstract

The geometries, energies, and vibrational frequencies of various isomers of HSO4−(H2O)n, n = 0–6 are calculated at various levels up to MP2/6-31+G*. These properties are studied as a function of increasing cluster size. The experimental and theoretical vibrational spectra are compared. The calculations help to explain the observed full-widths at half-height, the rather large temperature dependence of the S-OH stretching frequency, and the apparent discrepancy of the S-OH stretching and SOH deformation frequencies between ionic liquid and aqueous media.