Electron Impact Excitation of Atomic Oxygen and Atomic Hydrogen.

The absolute cross sections for the excitation of vacuum ultraviolet radiation by electron impact on atomic oxygen and atomic hydrogen are presented. Excitation functions from 0-300 eV for Ol(1304A), Ol(1027A), Ol(989A), Ol(1152A), Ol(878A), Oll(833A), Oll(718A), Oll(617A), Hl(1216A), Hl(1026A), Hl(973A), Hl(950A), and Hl(938A) multiplets are given. Representative spectra are shown. In this experiment, a flow of gas was dissociated by a microwave discharge tube before being admitted into a collision chamber where it was bombarded by an electron beam. The vacuum ultraviolet radiation which resulted from electron impact excitation of the dissociated gas was measured by a vacuum ultraviolet monochromator and VUV detector. The vacuum ultraviolet optical system was calibrated by using the dissociative excitation cross section data of O(,2) and N(,2) by electron impact. The Ol(1304A) emission cross section value of 2.8 x 10('-17) cm('2) at 100 eV and the Born-approximation value for the direct excitation cross section for the H(2p) state, 0.486 (pi)a(,o)('2), at 200 eV were used to normalize the relative cross section data obtained in this experiment. Possible aeronomical applications of the experimental cross sections are discussed in this thesis.