SPECTRAL-LINE SHAPE-PARAMETERS FAR HF IN A BATH OF AR ARE ACCURATELY PREDICTED BY A POTENTIAL INFERRED FROM SPECTRA OF THE VAN-DER-WAALS DIMER

An interaction potential for Ar-HF, which was recently determined from extensive spectroscopic data. for the van der Waals dimer and which includes dependence on the HF vibrational state, has been used with accurate close-coupling molecular scattering calculations to predict line shape parameters for the pure rotational and the fundamental and first overtone vibrational bands of HF in a bath of Ar. Agreement with experiment is good; in fact, considering inconsistencies among the experimental values; the theoretical values may be the more reliable. This confirms the accuracy of the Ar-HF interaction potential, including the dependence on the HF vibrational level which is sensitively probed by the line shift cross sections.