Year: 2020
Type: article
Abstract: We demonstrate that the effective Hamiltonians obtained with the downfolding procedure based on double unitary coupled cluster (DUCC) ansatz can be used in the context of Green's function coupled cluster (GFCC) formalism to calculate spectral functions of molecular systems. This combined approach (DUCC-GFCC) provides a significant reduction of numerical effort and good agreement with the corresponding all-orbital GFCC methods in energy windows that are consistent with the choice of active space. These features are demonstrated on the example of four benchmark systems: H2O, N2, CO, and trans-1,3-butadiene, where DUCC-GFCC calculations were performed for active spaces of various sizes.
Source: Molecular Physics
Authors: Nicholas P. Bauman, Bo Peng, Karol Kowalski
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2979087770