Low-energy proton stopping power ofN2,O2, and water vapor, and

Abstract

A modified local-plasma model, based on the works of Lindhard and Winther, and Bethe, Brown, and Walske is established. The Gordon-Kim model for molecular-electron density is used to calculate stopping power of N2, 02, and water vapor for protons of energy ranging from 40 keV to 2.5 MeV, resulting in good agreement with experimental data. Deviations from Bragg's rule are evaluated and are discussed under the present theoretical model.

Orientation Effects in Multiple Ionization of Molecules by Fast Ions

“…A distribution of deposited energies is characterized by its first (mean energy loss) and second (energy straggling) moments. We calculated the mean energy loss and the energy straggling using the well known local electron density approximation (LDA) of Lindhard and Scharff [20], which has been successfully used for a description of energy loss in ion-atom and ion-molecule collisions (see, for example, [21,22]). In this approximation every elementary volume of the target molecule is considered as a free electron gas with the density equal to the electronic density, r͑r͒.…”

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

“…The LDA approach [19] considers each volume element of the target at a given position 'r' as an independent electron plasma of uniform density ρ = ρ(r), where ρ(r) represents the electron density of the molecule. The average energy loss is estimated using the stopping power of an electron gas and this loss is integrated over the path [42][43][44]. The electron stopping power, in turn, is a function of ρ(r) and v. As LDA uses only the target ground state electron density, this approximation can be applied to molecules as well.…”