Projectile isotope effects on electronic stopping power: Harmonic Oscillator approach

Abstract

As kinematic momentum transfer in a collision depends on the projectile mass M1, the electronic stopping cross section of materials for swift ions should show an isotope effect. The effect is larger for large isotope mass differences and for high mean excitation energy of the target at low velocities, as long as the first Born approximation is still valid. The magnitude of the projectile isotope effect is evaluated using an harmonic oscillator approach in the first Born approximation for the stopping power, and is found to account for a difference of 1% between the stopping of protons and muons on He and Ne; and 0.7% on Al at a projectile energy of around 25 keV/amu.