Monte Carlo Classical Trajectory Calculation of the Rates of F-Atom Vibrational Relaxation of HF and DF

Rates of F-atom vibrational relaxation of HF and DF have been calculated for the temperature range 600–2000°K using Monte Carlo classical trajectory methods. The processes F+(D)HF(v)→ F+(D)HF(v−1), where v=1, 3, and 5 and F+HF(0)→ F+HF(1) were investigated. Agreement with available experimental data is excellent. The calculations show that vibrational de-excitation is due to vibration-rotation transfer and that excitation is due to translation-vibration transfer. Multiple-quantum transfers are found to occur in de-excitation of higher vibrational levels. A semiempirical valence-bond potential-energy surface was used. No adjustments were made to the surface to cause agreement between calculated and experimental energy-transfer results.