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K. Dimitriou, F. Aumayr, K. Katsonis, Hp. Winter, M. Chibisov, R. Janev, X. Urbain, F. Brouillard:
"Atomic data for H⁺+He(1s²), He(NLM) collisions: single ionization, excitation and charge exchange cross sections";
Atomic and Plasma-Material Interaction Data for Fusion, 13 (2007), 88 - 101.

Classical trajectory Monte Carlo (CTMC-) calculations have been performed for single ionisation and excitation of ground-state helium atoms by protons in the impact energy region of 5 - 200 keV. The calculated data are compared with available experimental data: for ionisation they are close to each other, while for excitation the calculated data are larger by up to a factor of two. For excitation into high quantum numbers we observe a n-3 scaling law for our CTMC calculations. In addition, cross sections for excitation and charge exchange in slow collisions of protons with He(1s,NLM) excited atoms (N = 2, 3, 4) have been calculated in the collision velocity range 106 - 108 cm/s by using the molecular orbital close-coupling (MOCC) method, with analytically calculated coupling matrix elements in the asymptotic region of internuclear distance. There are no results from other sources for these cross sections for comparison. The cross section data obtained in CTMC and MOCC calculations are presented in graphical and tabular form.