Quasiclassical trajectory method for molecular scattering processes: necessity of a weighted binning approach

It is shown that the standard binning method utilized in the classical study of scattering processes dealing with more than three atoms, which consists in rounding the product vibrational actions (the xiʹs) to their nearest (the niʹs), is not appropriate when the total energy disposal in the products is too low for the classical and quantum densities of vibrational states to be equal. Two alternative approaches are proposed which account as simply as possible for both the whole set of trajectories performed and the quantal nature of the vibrational energy.