Doubly Excited Feshbach States ofCl−

Abstract

An investigation of doubly excited states of the negative chlorine ion using the method of configuration interaction has located several Feshbach autodetaching resonances in the energy region 8.5-12.6 eV. Dominant two-particle excitations considered include $3{p}^{2}\ensuremath{\rightarrow}4{s}^{2}$, $4s4p$, $4{p}^{2}$, and $5{s}^{2}$. The results obtained are useful in interpreting the recent experimental structure observed in the electron spectrum resulting from collisions of ground-state ${\mathrm{Cl}}^{\ensuremath{-}}$ ions with helium- and hydrogen-gas targets.