Calculation of the discrete component of resonance states in negative ions by variation of nuclear charges

A method for obtaining the discrete component of resonance states in negative molecular ions is described. It is based on standard MRD-CI type calculations and especially designed for treating larger molecular systems. The resonance is thereby stabilised by increased nuclear charge. The method is applied to the calculation of N 2 - in its 2 Pi g ( pi u 4 pi g ) and 2 Pi u ( pi u 3 Ss 2 ) resonance states.