Effects of autoionizing resonances on electron-impact excitation rates for Be-like ions

Publisher Website
Google Scholar
Abstract
The effects of autoionizing resonances on the electron-impact excitation rates for n=2 to n=2 intrashell transitions in Be-like ions have been studied for six ions with atomic numbers Z=30, 34, 36, 42, 47, and 54. The resonance contributions to the excitation rates were calculated in the isolated-resonance approximation. Detailed Auger and radiative rates were evaluated in the multiconfiguration Dirac-Fock model. Results are compared with background rates from the Coulomb-Born-exchange approximation. Autoionizing resonance have been found to enhance the electron-impact excitation rates by a factor of 2–4 for the electric-dipole-forbidden transitions, while for dipole-allowed transitions, the resonance effects amount to only a few percent of these rates.