Nonadiabatic dynamical studies of the rotational Raman spectrum of H2 in water

Abstract

The rotational Raman spectrum of H₂ in liquid H₂O and D₂O have been calculated using our nonadiabatic time correlation function results presented in earlier work [L. Xiao and D. F. Coker, J. Chem. Phys. 100, 8646 (1994)]. The rotational potential experienced by the H₂ molecule in this solvent environment is so anisotropic that classical solvent fluctuations not only drive transitions between orientational basis states, but mixing of states from different total angular momentum levels is also considerable. Our nonadiabatic calculations are able to quantitatively reproduce the experimental rotational Raman line shapes and their trends with solvent isotopic substitution. We demonstrate that nonadiabatic transitions between adiabatic rotor states play a key role in smoothing out artificial structures predicted in the static and adiabatic limit spectra.