Proposed Theory of Calculating the Energy of Negative-Ion Resonant Elastic Scattering States and of the Pre-Ionization States of Electronic Spectroscopy

Abstract

In elastic electron‐impact experiments, with the subsequent formation of negative ions and pre‐ionization spectral theory, similar theoretical problems arise. In both, autoionizing states of lifetime 10⁻¹⁴ to 10⁻¹² sec are of basic importance, and also the variation principle is not applicable to the problem of the calculation of the energy. We propose here an approximate variation principle for calculating their energies and wavefunctions. The ideas are based on physical and nonanalytic arguments and tested successfully on the problem of elastic scattering of electrons by the hydrogen molecule, with an explanation of the H₂^— resonances observed by Simpson et al. and the H^— resonance observed by Schulz.