Principal Quantum Number Dependence for Electron–Hydrogen Collisions

Abstract

Over the last two decades, there has been considerable interest in the electron-atom scattering problem. Most of this work has concentrated on elastic scattering and excitation of the lowest energy states. However, due to recent technological advances, it is now becoming possible to examine experimentally the excitation of higher lying states. The important question then concerns whether these higher states contain new information. It has been argued that the scattering amplitudes for electron-helium excitation should scale with principal quantum and thus contain no new information. The purpose of this work is to examine the n-dependence for electron-hydrogen scattering. The converged-close-coupling and second-order distorted-wave methods have been used to calculate scattering amplitudes for excitation of the n = 2, 3 and 4 levels of the hydrogen atom. The n-dependence of the integrated cross sections, differential cross sections and angular correlation parameters will be discussed for energies from threshold to 500 eV.

Electron-impact excitation of Rydberg and valence electronic states of nitric oxide: I. Differential cross sections

“…Indeed, for both the nsσ and npπ series of states the n = 4 and n = 5 members have quite similar differential cross section magnitudes over the entire range of measured scattering angles. Hence, analogous with the atomic hydrogen results of Bubelev et al [70,71], we conclude that for NO we cannot see the Rydberg series of states exhibiting a systematic cross section dependence with the series number n.…”

“…The fact that the DCSs, at a given E 0 , for all the members of a given Rydberg series of states, whether it be the nsσ, npπ, npσ, ndσ, ndπ or ndδ etc series [69], appear to have qualitatively the same angular distribution (see for example figures 5 and 6) suggests that there may be a scaling of these cross sections with the Rydberg series number n. There have been extensive theoretical studies on electron scattering from atomic hydrogen [70,71] and helium [72], to ascertain if there is a scaling of the cross sections with the principal quantum number n. The importance of this is manifest, if such a factorization exists then there would be no need to study the higher-order quantum states as all the scattering information could be gleaned from the lower-lying levels.…”