Excitation of the n=4 Levels of He⁺ by the Impact of H⁺, He⁺ and He²⁺ Ions

Abstract

The emission cross sections of Hell (4→3) 4686 Å line by the incident beams of 0.5-1.5 MeV H⁺, 1.0-2.5 MeV He⁺ and 1.0-2.0 MeV He²⁺ are studied. By measuring the lateral distribution of the light intensity, the excitation of He⁺ (n＝4) levels is found to be caused by direct collision. The emission cross section by the proton impact is due to the ″ionization process″ and shows an E⁻¹ dependence, while that by the helium ion impact is due to the “charge transfer process” as well as the “ionization process” and shows a steeper energy dependence.