Electron scattering by Ca atoms and photodetachment ofCa−ions: An R-matrix study

Abstract

We have performed close-coupling calculations on electron scattering by Ca atoms and on photodetachment of ${\mathrm{Ca}}^{\mathrm{\ensuremath{-}}}$ ions by using a six-state ${(}^{1}$S- $^{3}\mathrm{\ensuremath{-}}$ $^{3}\mathrm{\ensuremath{-}}$ $^{1}\mathrm{\ensuremath{-}}$ $^{1}\mathrm{\ensuremath{-}}$ $^{1}\mathrm{P}$) R-matrix method. We predict a strong interaction between (${4\mathrm{s}}^{21}$S+\ensuremath{\epsilon}d${)}^{2}$D and (${4\mathrm{s}4\mathrm{p}}^{3}$P+\ensuremath{\epsilon}p${)}^{2}$D channels that gives rise to two relatively broad resonance peaks in the d-wave cross section. In addition, one obtains a strong and a weak peak in the total scattering cross section. Our calculations on the photodetachment cross section of ${\mathrm{Ca}}^{\mathrm{\ensuremath{-}}}$ ions yield results that are in good qualitative agreement with the experimental data by allowing for the opening of a detachment channel connected to the excited state ${4\mathrm{s}4\mathrm{p}}^{3}$P.