MetastableC22−Dianion

A metastable molecular dianion ${\mathrm{C}}_2^{2-}$ in a closed-shell ${}_{}{}^1{}_{}{}^{}\Sigma _g^{+}{}_{}{}^{}$ state has been found. Using a complex absorbing potential in conjunction with a multireference configuration interaction wave function, the resonance position and width are calculated and their dependence on the nuclear charge Z is examined. Based on our findings the interpretation of a recent scattering experiment is questioned and an alternative experiment is proposed.