Barkas effect in the stopping power for ions with different ionization degrees

C. D. ARCHUBI; I. ABRIL; R. GARCÍA MOLINA; N. R ARISTA

Lanzhou

Conferencia; XXVIII Internacional Conference on Photonic, Electronic and Atomic Collisions (ICPEAC 2013); 2013

Comité ICPEAC 2013

The Barkas effect in the electronic stopping power for dressed projectiles moving in a free electron gas is studied for a wide range of velocities v on the basis of a classical dynamics treatment. A large set of numerical simulations were made for different projectiles and degrees of ionization. We find that the Barkas factor increases at high energies with the number of projectile bound electrons, whereas its velocity dependence changes from the v3 behavior for bare projectiles to a v2 behavior for neutral ones. Interesting effects of curve crossings in the Barkas factor at different degrees of ionization as function of the projectile velocity are observed. A simple scaling law for neutral and fully ionized projectiles is also derived.