General Correlated Geminal Ansatz for Electronic Structure Calculations: Exploiting Pfaffians in Place of Determinants
| Autor: | Claudio Genovese, Kousuke Nakano, Tomonori Shirakawa, Sandro Sorella |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Chemical Physics (physics.chem-ph)
Pfaffian wave function Quantum Monte Carlo 010304 chemical physics Geminal Strongly Correlated Electrons (cond-mat.str-el) FOS: Physical sciences Pfaffian Electronic structure Computational Physics (physics.comp-ph) 01 natural sciences Article Computer Science Applications Settore FIS/03 - Fisica della Materia Condensed Matter - Strongly Correlated Electrons Physics - Chemical Physics 0103 physical sciences Statistical physics Physical and Theoretical Chemistry Physics - Computational Physics Ansatz Mathematics |
| Zdroj: | Journal of Chemical Theory and Computation |
| ISSN: | 1549-9626 |
| Popis: | We propose here a single Pfaffian correlated variational ansatz, that dramatically improves the accuracy with respect to the single determinant one, while remaining at a similar computational cost. A much larger correlation energy is indeed determined by the most general two electron pairing function, including both singlet and triplet channels, combined with a many-body Jastrow factor, including all possible spin-spin spin-density and density-density terms. The main technical ingredient to exploit this accuracy is the use of the Pfaffian for antisymmetrizing an highly correlated pairing function, thus recovering the Fermi statistics for electrons with an affordable computational cost. Moreover the application of the Diffusion Monte Carlo, within the fixed node approximation, allows us to obtain very accurate binding energies for the first preliminary calculations reported in this study: C$_2$, N$_2$ and O$_2$ and the benzene molecule. This is promising and remarkable, considering that they represent extremely difficult molecules even for computationally demanding multi-determinant approaches, and opens therefore the way for realistic and accurate electronic simulations with an algorithm scaling at most as the fourth power of the number of electrons. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|