Electronic interactions and nuclear scattering effects in the stopping power of carbon for fragmented H2+ projectiles

The stopping power of amorphous carbon for fragmented swift H2+ molecular ions has been carried out using a Molecular Dynamics code to follow the trajectory of each fragment proton as it moves through the target. We consider the interaction of each proton with the target electrons, the Coulomb repulsion between both protons and the vicinage effects due to the wake potential created by its partner proton. The nuclear scattering with the target nuclei was also taken into account using a Monte Carlo simulation code. The stopping ratio distribution of the proton fragments has been obtained as a function of the incident energy and target thickness. Comparison of the calculated mean stopping ratio with experimental data shows a good agreement.We would like to thank the Spanish Dirección General de Investigación Científica y Técnica (projects PB95-0689 and PB96-1118) for financial support, the Instituto de Cooperación Iberoamericana for a grant to CDD, and the Conselleria d'Educació i Ciència de la Generalitat Valenciana for a visiting professor fellowship to NRA under the program PROPIO