Infrared studies of CO2 doped Xe solutions in gas, liquid and solid phases. The fundamental ν3 band and the Coriolis perturbed Fermi doublet (ν1+ν21, ν1+ν211)

Abstract

The IR absorption spectra of CO2 doped Xe solutions have been recorded in the range of the fundamental ν3(Σu) band and of the Coriolis perturbed ν1+ν21, ν1+ν211(πu) Fermi doublet (ν1+ν2≈3ν2) in gas, liquid and solid phases. The characteristic transformation and rapid narrowing of the ν3 band, observed in the gas to liquid phase transition, shows marked hindering of the rotational motion of the CO2 molecule in dense Xe mixtures. It was found that the liquid to solid phase transition is accompanied by noticeable broadening of the ν3 band. The rotational motion of CO2 is not frozen in solid Xe at least near the freezing point. This is in contrast with sharp narrowing of the vibrational bands and so with blocking up rotations in the case of a heavier CS2 guest in the solid Xe host just below the freezing point. The intensity ratio A(ν1+ν21)/A(ν1+ν211) of the Coriolis perturbed ν1+ν21, ν1+ν211 doublet reveals the noticeable increase from 8±1 in a low density gas to 18±2 in the liquid phase. The results obtained suggest remarkable modification of the second-order Coriolis coupling in the case of CO2 doped dense liquid Xe.