Collisions between electrons and H₂⁺ ions. IV. Measurements of cross sections for dissociative ionization

For pt.III, see abstr. A64132 of 1972. Cross sections for the dissociative ionization of H₂⁺ by electron impact have been measured for interaction energies below 940 eV. A source was used which produced H₂⁺ ions under clearly defined conditions. The cross section attained a maximum value of 0.2 pi a₀² at 103 eV which is in fairly good agreement with classical predictions by Alsmiller (1962) and Mathur et al. (1970). A Bethe plot of the results rolls over in a way which suggests that the Bethe approximation will only be valid for this reaction for energies of at least several hundred eV.