Effects of Ltot-conservation and quantization of vibrational energy in statistical simulations of the reaction Cs∗ (72P12

The crossed beam experiments of Lʹ Hermite et al.(1990–1991) on the reaction Cs ∗ (72P12,32) + H2 → CsH + H are simulated using the statistical algorithm RRKM-SA. Good agreement between the experimental and calculated rotational quantum number distributions as well as the fractional values of total energy in different degrees of freedom, are obtained. Quantization of vibrational energy is included in the otherwise classical calculations and is shown to be important. The reaction is found to be statistical but with a very strong dependence on the conservation of total angular momentum. In a so-called triangular plot it can be seen that it is the low total available energy that makes the angular momentum restrictions so important. This constraint also means that a considerable portion of the translational energy at the exit centrifugal barrier is instead found in molecular and complex rotational energy. Branching ratios are calculated for the reaction involving both Cs(72P12) and Cs(72P32) and good agreement with the approximate experimental values are obtained.