Comparison between the analysis of the asymptotic wavepacket and the associated flux for the calculation of kinetic-energy-releases function

摘要

The kinetic-energy-releases (KER) distribution function of the fragment is an important observable in the molecular dynamics. In theory, there are several different methods to calculate the KER distribution function or spectrum, which could be generally divided into two classes: One is based on the analysis of the asymptotic wavepacket ("projection method") and the other is on the analysis of the associated flux ("flux method"). By taking the above-threshold dissociation of the HeH+ (v = 8) molecule as an example, we compared these two classes of methods. Based on evenly separated Fourier grid representation, the KER distribution calculated via the projection method F-Proj(E-k) is the same as the one calculated via the flux method F-Flux(E-k). The relationship between F-Proj(E-k) and the distribution of the projection of the asymptotic wavepacket onto the energy eigenstates of the quasicontinuum, P-Proj(E-k), and the relationship between F-Flux(E-k) and the distribution of the dissociation probability P-Flux(E-k) from the cumulation of the associated flux, are determined.