H2O-HF dimer rotational spectra: New measurements and re-analysis

Abstract

New measurements of the H${}_2$O-HF dimer high resolution absorption spectrum are performed using a relatively warm (240–260 K) equilibrium gas mixture with two complementary spectrometers: a video spectrometer and spectrometer with radio-acoustic detection. Positions of over hundred H${}_2$O-HF lines in the 158–345 GHz range are refined (their uncertainty is reduced by about order of magnitude) and several tens of lines are newly measured. These data are re-fitted together with previous measurements giving a refined set of constants of effective Hamiltonian which characterizes the dimer intermolecular dynamics. The new data improves significantly (from 100 to about 10 kHz) the accuracy of rotational constants corresponding to separate series of lines with fixed $K_a$.