The interaction-induced Q-branch

Abstract

Binary impact theory, perturbation theory and sudden modulation theory are employed to estimate the interaction-induced Q-branch observed in spectra of diatomic dipolar molecules in dense gases and liquids. The size of the effect observed in hydrogen halide solutions proves that strong interactions exist between the solutes and the medium. However, thermal motion modulating the interaction in its magnitude and direction can in some solutions average it to zero, thus restoring the spectrum typical for a free rotor.