Efficient excitations and spectra within a perturbative renormalization approach

TY - JOUR

T1 - Efficient excitations and spectra within a perturbative renormalization approach

AU - Booth, George

PY - 2020/9/4

Y1 - 2020/9/4

N2 - We present a self-consistent approach for computing the correlated quasiparticle spectrum of charged exci- tations in iterative O[N5] computational time. This is based on the auxiliary second-order Green’s function approach [O. Backhouse et al., JCTC (2020)], in which a self-consistent effective Hamiltonian is constructed by systematically renormalizing the dynamical effects of the self-energy at second-order perturbation theory. From extensive benchmarking across the W4-11 molecular test set, we show that the iterative renormalization and truncation of the effective dynamical resolution arising from the 2h1p and 1h2p spaces can substantially improve the quality of the resulting ionization potential and electron affinity predictions compared to bench- mark values. The resulting method is shown to be superior in accuracy to similarly scaling quantum chemical methods for charged excitations in EOM-CC2 and ADC(2), across this test set, while the self-consistency also removes the dependence on the underlying mean-field reference. The approach also allows for single-shot computation of the entire quasiparticle spectrum, which is applied to the benzoquinone molecule and demon- strates the reduction in the single-particle gap due to the correlated physics, and gives direct access to the localization of the Dyson orbitals.

AB - We present a self-consistent approach for computing the correlated quasiparticle spectrum of charged exci- tations in iterative O[N5] computational time. This is based on the auxiliary second-order Green’s function approach [O. Backhouse et al., JCTC (2020)], in which a self-consistent effective Hamiltonian is constructed by systematically renormalizing the dynamical effects of the self-energy at second-order perturbation theory. From extensive benchmarking across the W4-11 molecular test set, we show that the iterative renormalization and truncation of the effective dynamical resolution arising from the 2h1p and 1h2p spaces can substantially improve the quality of the resulting ionization potential and electron affinity predictions compared to bench- mark values. The resulting method is shown to be superior in accuracy to similarly scaling quantum chemical methods for charged excitations in EOM-CC2 and ADC(2), across this test set, while the self-consistency also removes the dependence on the underlying mean-field reference. The approach also allows for single-shot computation of the entire quasiparticle spectrum, which is applied to the benzoquinone molecule and demon- strates the reduction in the single-particle gap due to the correlated physics, and gives direct access to the localization of the Dyson orbitals.

M3 - Article

SN - 1549-9618

JO - Journal of Chemical Theory and Computation

JF - Journal of Chemical Theory and Computation

M1 - 10.1021/acs.jctc.0c00701

ER -