Real-time coupled-cluster approach for the cumulant Green's function

Journal Article · Tue Nov 10 00:00:00 EST 2020 · Journal of Chemical Theory and Computation

DOI:https://doi.org/10.1021/acs.jctc.0c00639· OSTI ID:1716512

Vila, Fernando D. ^[1]; Rehr, John J. ^[1]; Kas, Joshua J. ^[1]; Kowalski, Karol ^[2]; Peng, Bo ^[2]

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1. University of Washington
2. BATTELLE (PACIFIC NW LAB)

Green’s function methods within many-body perturbation theory provide a general framework for treating electronic correlations in excited states. Here we investigate the cumulant form of the one-electron Green’s function based on the coupled-cluster equation of motion approach in an extension of our previous study. The approach yields a non-perturbative expression for the cumulant in terms of the solution to a set of coupled first order, non-linear differential equations. The method thereby adds non-linear corrections to traditional cumulant methods linear in the self energy. The approach is applied to the core-hole Green’s function and illustrated for a number of small molecular systems. For these systems we find that the non-linear contributions lead to significant improvements both for quasiparticle properties such as core-level binding energies, as well as the satellites corresponding to inelastic losses observed in photoemission spectra.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1716512
• Report Number(s): PNNL-SA-153807
• Journal Information: Journal of Chemical Theory and Computation, Vol. 16, Issue 11
• Country of Publication: United States
• Language: English