Real-valued continuum remover potential: An improved L2-stabilization method for the chemistry of electronic resonance states

We describe an efficient ab initio L2-stabilization method for computing the real part of the complex potential energy surface of electronic resonance state. Unlike most other commonly used stabilization methods, without repeating the eigenvalue calculation for stabilizing or extrapolating the eigenvalues, the new method offers basis set limit calculations. The non-interaction region of the metastable system is perturbed by an artificial potential which avoids the variational collapse of resonance wavefunction to its free-electron descriptions. This makes possible the use of all available bound-state methods for electronic resonance states. The method is best illustrated with Feshbach- and shape-type electronic resonance states.