Doubly excited states ofH−in parallel electric and magnetic fields

Abstract

Doubly excited ${}^{1}{S}^{e}$ and ${}^{1}{D}^{e}$ Feshbach resonances of ${\mathrm{H}}^{\mathrm{\ensuremath{-}}}$ lying below the $\mathrm{H}(N=3)$ threshold under the influences of external electric and magnetic fields in parallel directions are investigated theoretically using a method of complex-coordinate rotation. Products of Slater-type orbitals are used to represent the two-electron wave functions, with ${l}_{\mathrm{max}}=9$ being employed for the individual electron. Block matrices with up to ${L}_{\mathrm{max}}=5$ including ${}^{1}{S}^{e},$ ${}^{1}{P}^{o},$ ${}^{1}{D}^{e},$ ${}^{1}{F}^{o},$ ${}^{1}{G}^{e},$ and ${}^{1}{H}^{o}$ states are used. Convergence behavior for the resonance parameters (resonance energy and width) is examined by using different values of ${L}_{\mathrm{max}}.$ Results for the combined electric and magnetic field effects on the ${M}_{L}=0$ components of the ${}^{1}{S}^{e}(1)$ and ${}^{1}{D}^{e}(1)$ Feshbach resonances are reported.