Is the Bethe-Salpeter Formalism Accurate for Excitation Energies? Comparisons with TD-DFT, CASPT2, and EOM-CCSD.

摘要: Developing ab initio approaches able to provide accurate excited-state energies at a reasonable computational cost is one of the biggest challenges in theoretical chemistry. In that framework, Bethe–Salpeter equation approach, combined with GW exchange-correlation self-energy, which maintains same scaling system size as TD-DFT, has recently been focus rapidly increasing number applications molecular Using proposed set encompassing excitation many kinds [J. Phys. Chem. Lett. 2016, 7, 586–591], we investigate here performances BSE/GW. We compare these results CASPT2, EOM-CCSD, and TD-DFT data show BSE/GW provides an accuracy comparable two wave function methods. It particularly remarkable equally efficient for valence, Rydberg, charge-transfer excitations. contrast, it poor description triplet excited states, EOM-CCSD CASPT2 clearly outperform This contribution therefore supports use approach spin-conserving transitions.