On the problem of a “vibrational rainbow” origin in differential cross sections for atom-molecular scattering in keV region

The numerical study of inelastic differential cross section for $\mathrm{He}-\mathrm{N}_2$ system by the molecular dynamics method are performed for the reduced scattering angles $\tau[10,40]$ eV rad, collision energy $E\sim1$ keV. Spherical-symmetrical potentials for two excited and ground states are used. It is shown that this model permits to reproduce quantitatively the experimental shift of rainbow maxima in angular distributions vs energy of He beam if we suppose that the second excited state consists of the large amount of very close situated terms. It is emphasized that another cause of this dependence may be an ionization of any particle. To choose from these two mechanisms it is necessary to perform supplementary measurement to study ionization effects in $\mathrm{He}-\mathrm{N}_2$ collisions in keV rogion.