Excitation Processes in Helium Induced by Impact of Deuterons and Protons

The excitation of helium atoms by impact of protons and deuterons is examined in the energy range from 40-200 kev. The cross sections of some ¹S, ¹D and the 3¹P state are determined. The excitation of the 2¹P-4¹S line attains a broad maximum at 65 kev for protons, and at 115 kev for deuteron excitation. The 3³D state appears to be weakly populated by direct D⁺ excitation; at 130 kev D⁺ energy, Q(3³D)≤2×10^-20 cm². Inelastic collisions between excited helium and foreign atoms bringing about the transition from singlet to triplet states are discussed.