Production of Excited Hydrogen Atoms by Impact of Fast Electrons on Water Vapor

Abstract

Lyman-α and Balmer-α, β, γ, and δ radiation has been observed resulting from dissociative excitation of water vapor by fast electrons. Absolute cross sections for emission of this radiation are reported in the electron energy range from 50–6000 eV. The results are analyzed by means of the Bethe approximation. Of all the relevant dissociative states of the molecule formed during the collision process, those which are populated by optically allowed transitions predominate. The relatively large cross sections for dissociative excitation producing excited hydrogen atoms may indicate the importance of such species in the radiolysis of water.