Can $GW$ Handle Multireference Systems?
| Autor: | Ammar, Abdallah, Marie, Antoine, Rodríguez-Mayorga, Mauricio, Burton, Hugh G. A., Loos, Pierre-François |
|---|---|
| Rok vydání: | 2024 |
| Předmět: | |
| Zdroj: | J. Chem. Phys. 160, 114101 (2024) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1063/5.0196561 |
| Popis: | Due to the infinite summation of bubble diagrams, the $GW$ approximation of Green's function perturbation theory has proven particularly effective in the weak correlation regime, where this family of Feynman diagrams is important. However, the performance of $GW$ in multireference molecular systems, characterized by strong electron correlation, remains relatively unexplored. In the present study, we investigate the ability of $GW$ to handle closed-shell multireference systems in their singlet ground state by examining four paradigmatic scenarios. Firstly, we analyze a prototypical example of a chemical reaction involving strong correlation: the potential energy curve of \ce{BeH2} during the insertion of a beryllium atom into a hydrogen molecule. Secondly, we compute the electron detachment and attachment energies of a set of molecules that exhibit a variable degree of multireference character at their respective equilibrium geometries: \ce{LiF}, \ce{BeO}, \ce{BN}, \ce{C2}, \ce{B2}, and \ce{O3}. Thirdly, we consider a \ce{H6} cluster with a triangular arrangement, which features a notable degree of spin frustration. Finally, the dissociation curve of the \ce{HF} molecule is studied as an example of single bond breaking. These investigations highlight a nuanced perspective on the performance of $GW$ for strong correlation, depending on the level of self-consistency, the choice of initial guess, and the presence of spin-symmetry breaking at the Hartree-Fock level. Comment: 11 pages, 4 figures |
| Databáze: | arXiv |
| Externí odkaz: |
|