Use of the positive-ion potential to analyze doublet states

To compute the geometry of radicals in the ground and excited states of partial type, it is proposed to use a one-electron positive-ion function as cores. The efficiency of the method is illustrated by an example computing the radicals BH2, NH2, NH 3 + , CH3, FH2, for which both self-consistent solutions and solutions using the frozen ion core were obtained in the CNDO/BW approximation. Analysis of the results obtained permits the deduction that the error associated with using non-self-consistent functions does not exceed the error of the method itself.