Translational energy distribution and production mechanism of H* and D* produced by controlled electron impact on water and heavy water

Abstract

The high resolution spectra of the Balmer lines of H* (n=3,4) and D* (n=3,4) have been measured with the use of a Fabry–Perot interferometer. Translational energy distributions of H* and D* calculated from their Doppler profiles have four components; their peaks lie at about 0.5, 4, 2, and 6–8 eV. There are four thresholds for the formation of H* (n=4) and D* (n=4) at about 18.7, 25.5, 31.3, and 38.9 eV. The production mechanisms of these components have been assigned to dissociation through Rydberg states converging to some ionic states of water such as the B̃ 2B2, 2B1, 2A1, and doubly ionized states, respectively.