Vibrational relaxation of highly excited diatomics. VI. DF(9≤v≤12)+N2, CO, CO2, and N2O and HF(v=5–7)+CO

Vibrational relaxation rate constants are determined for DF(v=9–12) by Q=N2, CO, CO2, and N2O and for HF(v=5–7) by CO using the fast flow infrared chemiluminescence technique. The rate constants range from 0.6 to 35×10−11 cm3 s−1, and with the exception of Q=N2, the energy transfer probabilities P per gas-kinetic (Lennard-Jones) collision are large 0.4<P<1.0. The vibrational energy gap ΔE is small for the DF(v) relaxation processes and the v dependence of kQv, v−1 is much weaker than that for HF(v). The data suggest independent effects based on ΔE and on v which partially cancel each other for DF, but not for HF. The initial, unrelaxed v distribution for the D+F2→DF(v≤13)+F reaction is found to peak at v=9, in disagreement with earlier experimental studies but in agreement with recent theoretical work.