ChemRxiv
These are preliminary reports that have not been peer-reviewed. They should not be regarded as conclusive, guide clinical practice/health-related behavior, or be reported in news media as established information. For more information, please see our FAQs.
1/1
2 files

Excited-State Geometry Optimization of Small Molecules with Many-Body Green's Functions Theory

preprint
submitted on 17.10.2020, 09:21 and posted on 19.10.2020, 10:41 by Onur Çaylak, Björn Baumeier
We present a benchmark study of gas phase geometry optimizations in the excited states of carbon monoxide, acetone, acrolein, and methylenecyclopropene using many-body Green's functions theory within the GW approximation and the Bethe-Salpeter Equation (BSE). We scrutinize the influence of several typical approximations in the GW-BSE framework: using of one-shot G0W0 or eigenvalue self-consistent evGW, employing a fully-analytic approach or plasmon-pole model for the frequency dependence of the electron self-energy, or performing the BSE step within the Tamm--Dancoff approximation. The obtained geometries are compared to reference results from multireference perturbation theory (CASPT2), variational Monte Carlo (VMC), second-order approximate coupled cluster (CC2), and time-dependent density-functional theory (TDDFT). We find overall a good agreement of the structural parameters optimized with the GW-BSE calculations with CASPT2, with an average relative error of around 1% for the G0W0 and 1.5% for the evGW variants, respectively, while the other approximations have negligible influence. The relative errors are also smaller than those for CC2 and TDDFT with different functionals and only larger than VMC, indicating that the GW-BSE method does not only yield reliable excitation energies but also geometries.

Funding

Innovational Research Incentives Scheme Vidi of the Netherlands Organisation for Scientific Research (NWO) with project number 723.016.002

NWO and the Netherlands eScience Center project number 027.017.G15, within the Joint CSER and eScience program for Energy Research (JCER 2017)

History

Email Address of Submitting Author

b.baumeier@tue.nl

Institution

Eindhoven University of Technology

Country

Netherlands

ORCID For Submitting Author

0000-0002-6077-0467

Declaration of Conflict of Interest

None.

Exports

Logo branding

Exports