Interaction of protons with the C₆₀molecule: calculation of deposited energies and electronic stopping cross sections (<i>v</i>⩽5 au)

Abstract

The energy deposited by a proton in a C60 molecule is calculated over a broad collision velocity range from 0.1 to 5 au, using the free-electron gas model of Lindhard and Winther (1964 Mat. Fys. Medd. K Dan. Vidensk. Selsk. 34) and the C60 electron density distribution calculated by Puska and Nieminen. The energy lost by the proton is maximum near 1.8 au collision velocity in contrast with the saturation found in the low-velocity regime, in the 0.25-0.5 au velocity range, by Kunert and Schmidt. From the impact parameter dependence we deduce the distributions of deposited energies, the averaged energy losses and the C60 electronic stopping cross sections. It is found that the C60 molecule behaves as a carbon foil giving very similar absolute stopping cross sections per atom.