LINESHAPE PARAMETERS OF HE-BROADENED AND KR-BROADENED HF LINES IN THE FUNDAMENTAL-BAND

The spectral lineshapes for the P(6), P(8), P(9), R(7), and R(8) transitions of the fundamental band of HF in the presence of He and Kr buffer gases have been measured using a tunable difference-frequency laser spectrometer. For the light He perturber, the lineshapes are closely fitted by the diffusional Galatry (soft collision) and Rautian (hard collision) profiles incorporating the Dicke collisional narrowing of the Doppler distribution. For the heavy Kr perturber, the observed lineshape asymmetries have been modeled by modified Rautian or Galatry profiles which account for statistical correlation between velocity- and state-changing collisions. The speed dependence of collisional cross sections has also been considered through a generalized Voigt profile. Finally, the broadening, shifting, Dicke narrowing, and asymmetry coefficients have been derived from the best lineshape models used. (C) 1995 Academic Press, Inc.