Vibrational relaxation of highly excited diatomics. IV. HF(v=1–7) + CO2, N2O, and HF

Abstract

Vibrational relaxation rate constants are measured for HF(v=1–4) with Q=CO2, N2O, and HF by the fast flow infrared chemiluminescence technique using four HF(v) generating reactions whose initial vibrational distributions are found be be unrelaxed. The data are combined with earlier results for v=5, 6, and 7 to provide information on v dependence and quenching mechanism. The rate constants, kQv,v−1 range from 1.2×10−12 to 4.5×10−10 cm3 s−1 and increase with power law exponents n of 2.7 to 3.0 in k∝vn for all three quenchers. The relaxation is principally V–V for CO2 and N2O, but mainly V-R,T for HF, at least for the higher v levels. The relaxation rate constants are compared with theoretical estimates and form a valuable data base for future theoretical work.