Theoretical calculation of single ionization in collisions between protons and low- Z molecules at intermediate and high energies

Single ionization total cross sections for proton impact on N₂, CO, CH₄, and CO₂ are calculated by applying the continuum-distorted-wave-eikonal-initial-state model. Two different approximations have been considered for molecular targets: Bragg's additivity rule and a molecular representation of the bound state target wave function. In the latter, the cross section is approximated by a linear combination of atomic cross sections where the coefficients are determined from a population analysis and the binding energies have been extracted from experimental spectra. The results from both models are compared with experimental data.