Projected CAP / SAC ‐ CI method with smooth V oronoi potential for calculating resonance states

The complex absorbing potential (CAP)/symmetry‐adapted cluster‐configuration interaction (SAC‐CI) method has been combined with a smooth Voronoi potential, which was recently introduced in the extrapolation procedure, to locate π* resonance states of small‐ to medium‐size molecules. Here, the projected CAP/SAC‐CI method is combined with this potential and used to calculate the double‐bond and heteroaromatic π* resonances of acetaldehyde, butadiene, glyoxal, pyridine, pyrazine, and furan. As observed in the pilot applications, the corrected η ‐trajectories provide a stable resonance energy and width or lifetime regardless of the size parameter ( r cut ) of the smooth Voronoi potential. However, in general, the stabilization behavior of the trajectories is clearer for larger r cut values, which implies that the interaction of the CAP with the valence electrons is more advantageously addressed by a larger “cavity” size. © 2015 Wiley Periodicals, Inc.