Velocity dependence of fragmentation yields in proton–naphthalene collision and comparison with electronic energy loss calculation

Abstract

We investigate the interaction of a high velocity proton projectile (velocity between 1.41 and 2.68 au) with a gaseous naphthalene target. Fragmentation as well as multiple ionization yields are measured from the resulting mass spectra. The total fragmentation yields decrease with an increase in projectile velocity, which is in accordance with decreasing electronic stopping. Monte Carlo simulations have been performed within the framework of local density approximation to calculate the mean electronic energy loss. The theoretical cross sections are calculated from the energy loss distribution using a lower limit to internal energy deposition. The latter has been estimated from the resonant capture process measured concurrently for the same system. The velocity dependence of fragmentation yields obtained from the experiment is consistent with the modelled theoretical cross sections. Measurements of singly and doubly charged He projectiles with naphthalene show the effects of charge state equilibration and projectile charge screening.