TRANSLATIONAL-ENERGY-DEPENDENT EMISSION CROSS-SECTIONS OF EXCITED HYDROGEN-ATOMS PRODUCED IN ELECTRON-METHANE, ETHANE, ETHYLENE AND ACETYLENE COLLISIONS

Translational-energy dependence of emission cross sections was measure d for H (n = 4) produced in collisions of methane, ethane, ethylene a nd acetylene with electrons through analysis of Doppler profiles of th e Balmer-beta line. Emission cross sections were calculated for the tr anslational energies of 0-2, 2-4, 4-6, 6-8 and >8 eV. The translationa l-energy dependences of emission cross sections are similar for the fo ur hydrocarbons. The five segments can be classified into 3 groups. Th e first group, 0-2 eV, is dominant at lower electron energies. The sec ond group, 2-4 and 4-6 eV, is dominant above 40 eV. The third group, 6 -8 and >8 eV, has some contribution at higher electron energies.