MAIN FACTORS INFLUENCING THE RECOIL ENERGY-DISTRIBUTION IN THE PRODUCTS OF 3-ATOM REACTIONS GOVERNED BY LONG-RANGE FORCES AND PROCEEDING THROUGH LONG-LIVED COMPLEXES

We propose a simplified version of the classical statistical theory of three-atom reactions governed by long-range forces. This version is based on a partial treatment of total angular momentum conservation. We focus the developments on the determination of the recoil energy distribution of reactions performed in supersonic crossed-beam experiment. This distribution function is directly linked to the maximum values of the moduli of rotational and orbital angular momenta of the products consistent with their recoil energy and the total angular momentum disposal. Due to the simplicity of the present version, we can pinpoint the main factors which play a role in statistical reaction dynamics. It is shown that the shape of the translational energy distribution can be estimated essentially in terms of two mechanical parameters; the first one represents the available fraction of maximum angular momentum disposal in the products and the second gives a measure of the fraction of total angular momentum due to the rotation of the newly formed bond AB. Comparisons with exact calculations and experimental results are presented. They show that in addition to being able to determine propensity rules, our simple approach can even provide satisfying quantitative results. © 1995 American Institute of Physics.