DISTRIBUTIONS OVER THE 4S, 4P AND 4D SUBLEVELS AND THEIR EMISSION CROSS-SECTIONS OF THE EXCITED HYDROGEN-ATOM PRODUCED IN E-CH4 AND H2O COLLISIONS

Dissociation of CH4 and H2O induced in collisions with electrons was investigated by measuring decay curves of the intensity of the Balmer emission of the excited hydrogen atom H*(n=4). The azimuthal quantum number (s,p,d) distributions of H*(n=4) were obtained by a time-resolved single-photon counting method. The distribution (%) for methane is H*(4s):H*(4p):H*(4d)=42±4:4± 11:51 ±11 at the electron energy of 25-300 eV, and that for water is H*(4s):H*(4p):H*(4d)=27±5:15±11:55±11 at 23-300 eV. The emission cross sections of each sublevel were obtained at 35, 50, 100 and 300 eV. © 1990, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.