Publikace ÚTF

We propose a simple method for calculation of low-lying shape electronic resonances of polyatomic
molecules. The method introduces a perturbation potential and requires only routine bound-state type
calculations in the real domain of energies. Such a calculation is accessible by most of the free or
commercial quantum chemistry software. The presented method is based on the analytical continuation
in a coupling constant model, but unlike its previous variants, we experience a very stable and robust
behavior for higher-order extrapolation functions. Moreover, the present approach is independent of
the correlation treatment used in quantum many-electron computations and therefore we are able to
apply Coupled Clusters (CCSD-T) level of the correlation model.We demonstrate these properties on
determination of the resonance position and width of the 2Πu temporary negative ion state of diacetylene
using CCSD-T level of theory. C 2015 AIP Publishing LLC.