Emission cross sectionsfor H, C and He produced in He++ CH4 collisions

Abstract

Emission cross sections for hydrogen Lyman-α, -β,Balmer-α, -β, C(3s 3PJ'o→2p2 3PJ, 165.7 nm), C(2p3 3DJ'o→2p2 3PJ, 156.1 nm)and He(2p 1P1→1s2 1S0,58.4 nm) produced in He+ + CH4 collisions aremeasured in the energy range from 4 eV (cm) to 4000 eV (cm). Theemission cross sections of hydrogen Lyman and Balmer series have aplateau above 100 eV. The cross sections of helium and carbon linesdecrease rapidly with decreasing collision energy. The branching ratiowhen an excited hydrogen with n = 2 is produced is estimated to be2.5×10-2 at 4000 eV by using measured emission crosssections for Hα to Hε and byempirical relations.