Multiquantum vibration–vibration transitions in H 35Cl(n)+H 37Cl(0) and H 35Cl(n)+H 79Br(0)

Multiquantum transitions in the vibration–vibration energy exchange process H 35Cl(n)+H 37Cl(0)→H 35Cl(0)+H 37Cl(n) are shown to be quite efficient near room temperature. This result is due to the presence of strong molecular attraction and the condition of near resonance. At 300 K, the probability for n = 1 is 0.085, while that for n = 5 is 0.014, the difference being not great. For the nonresonant collision of H 35Cl(n)+H 79Br(0)→H 35Cl(0)+H 79Br(n), the probability for n = 1 is found to be very small compared to the near-resonant case and, furthermore, the probability for n = 2 is two orders of magnitude smaller than that for n = 1.