Quantum embedding theory in the screened Coulomb interaction: Combining configuration interaction with GW/BSE

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Abstract

We present a quantum embedding theory called dynamical configuration interaction (DCI) that combines wave function and Green's function theories. DCI captures static correlation in a correlated subspace with configuration interaction and couples to high-energy, dynamic correlation outside the subspace with many-body perturbation theory based on Green's functions. DCI takes the strengths of both theories to balance static and dynamic correlation in a single, fully ab initio embedding concept. The theory adds dynamic correlation around a fixed active space of orbitals with efficient O(N-5) scaling, while maintaining a multireference treatment of the active space. We show that treating high-energy correlation up to the GW and Bethe-Salpeter equation level is sufficient even for challenging multireference problems. Our theory treats ground and excited states on equal footing, and we compute the dissociation curve of N-2, the vertical excitation energies of small molecules, and the ionization spectrum of benzene in excellent agreement with high-level quantum chemistry methods and experiment.

Details

Original languageEnglish
Article number070801
Pages (from-to)1-6
Number of pages6
JournalPhysical Review Materials
Volume3
Issue number7
Publication statusPublished - 31 Jul 2019
MoE publication typeA1 Journal article-refereed

    Research areas

  • PERTURBATION-THEORY, EXCITED-STATES, ELECTRON, BUTADIENE, ETHYLENE, VALENCE, SPECTROSCOPY, BENCHMARKING, EXCITATIONS, EQUATION

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