A partially correlated strong collision model for velocity- and state-changing collisions application to Ar-broadened HF rovibrational line shape

High-resolution tunable laser measurements of rovibrational line shapes in Ar-broadened HF [A.S. Pine, J. Chem. Phys., 1994, 101, 3444] have shown the need of partially correlated Dicke narrowing models to accurately describe the observed asymmetries. A strong collision model accounting for both vel ocity- and state-changing mechanisms (VCD) and phase-changing ones (D), is presented. The resulting line shape justifies, on a physical basis, the emp irical model previously used to interpret the observed features. The presen t partially correlated strong collisional model leads to a clearer interpre tation of the characteristic parameters determined from the experiment for HF-Ar. Further theoretical calculations and experiments show that the resid ual discrepancies for the first rovibrational lines cannot be attributed to the speed dependence of the collisional line shape parameters. (C) 1999 El sevier Science Ltd. All rights reserved.