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

The spectral lineshapes for the P(6), P(8), P(9), R(7), and R(8) trans itions of the fundamental band of HF in the presence of He and Kr buff er 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 c ollision) profiles incorporating the Dicke collisional narrowing of th e Doppler distribution. For the heavy Kr perturber, the observed lines hape asymmetries have been modeled by modified Rautian or Galatry prof iles which account for statistical correlation between velocity- and s tate-changing collisions. The speed dependence of collisional cross se ctions has also been considered through a generalized Voigt profile. F inally, the broadening, shifting, Dicke narrowing, and asymmetry coeff icients have been derived from the best lineshape models used. (C) 199 5 Academic Press, Inc.