Electron impact excitation of the n=2 to n=3 transition in atomic hydrogen near threshold
Abstract
Close-coupling calculations of electron impact excitation of the n = 2 to n = 3 transition of atomic hydrogen at energies below the n = 4 threshold are presented. The algebraic variational close-coupling code of Morgan (1980) with an eighteen-state basis was used to obtain cross sections at eight impact energies from 2.04 to 2.45 eV, and calculations in a six-state close-coupling model were compared with the six-state calculations of Burke et al. (1967). The six-state values are found to be in satisfactory agreement with the exception of the singlet contribution to the 2s-3s transition. Near the n = 3 threshold the cross section obtained in the full calculation is found to be almost a factor of 2 lower than that predicted by Johnson (1972), thus explaining in part the discrepancy between Johnson's results and experiments on hydrogen plasmas. Estimates of rate coefficients based on the cross sections and assuming a Maxwellian velocity distribution, however, are shown to remain in disagreement with experiment.
- Publication:
-
Journal of Physics B Atomic Molecular Physics
- Pub Date:
- June 1980
- DOI:
- 10.1088/0022-3700/13/11/005
- Bibcode:
- 1980JPhB...13L.347H
- Keywords:
-
- Atomic Excitations;
- Electron Impact;
- Electron Transitions;
- Hydrogen Plasma;
- Plasma Physics;
- Maxwell-Boltzmann Density Function;
- Plasma Diagnostics;
- Plasma-Particle Interactions;
- Threshold Logic;
- Variational Principles;
- Plasma Physics