posted on 2020-10-20, 21:47authored byMushir Thodika, Nathan Mackouse, Spiridoula Matsika
Two-particle one-hole (2p-1h) resonances are elusive to accurate
characterization, their decay to the neutral state being a two-electron
process. Although in limited cases, single reference methods can be
used, a proper description of a 2p-1h resonant state entails a multiconfigurational
treatment of the reference wavefunction. In this work, we test the
performance of the orbital stabilization method to characterize the
2p-1h resonances found in water and benzene. We employ a set of two
multireference approaches, namely, the restricted active space self-consistent
field and the multireference configuration interaction, as well as
the single reference method equation of motion for electron attachment
coupled-cluster with singles and doubles, in the case of benzene.
We further explore the resonant channel mixing in benzene between
the B2g shape resonance and 2p-1h resonance, a phenomenon
which has been explored quite often in experimental studies.