Efficient Adiabatic Connection Approach for Strongly Correlated Systems: Application to Singlet–Triplet Gaps of Biradicals

0557671 - ÚFCH JH 2023 RIV US eng J - Journal Article
Drwal, D. - Beran, Pavel - Hapka, M. - Modrzejewski, M. - Sokól, A. - Veis, Libor - Pernal, K.
Efficient Adiabatic Connection Approach for Strongly Correlated Systems: Application to Singlet–Triplet Gaps of Biradicals.
Journal of Physical Chemistry Letters. Roč. 13, č. 20 (2022), s. 4570-4578. ISSN 1948-7185
Research Infrastructure: e-INFRA CZ - 90140
Institutional support: RVO:61388955
Keywords : RANDOM-PHASE-APPROXIMATION * 2ND-ORDER PERTURBATION-THEORY * MATRIX RENORMALIZATION-GROUP
OECD category: Physical chemistry
Impact factor: 5.7, year: 2022
Method of publishing: Open access

Strong electron correlation can be captured with multireference wave function methods, but an accurate description of the electronic structure requires accounting for the dynamic correlation, which they miss. In this work, a new approach for the correlation energy based on the adiabatic connection (AC) is proposed. The ACn method accounts for terms up to order n in the coupling constant, and it is size-consistent and free from instabilities. It employs the multireference random phase approximation and the Cholesky decomposition technique, leading to a computational cost growing with the fifth power of the system size. Because of the dependence on only one- and two-electron reduced density matrices, ACn is more efficient than existing ab initio multireference dynamic correlation methods. ACn affords excellent results for singlet–triplet gaps of challenging organic biradicals. The development presented in this work opens new perspectives for accurate calculations of systems with dozens of strongly correlated electrons.
Permanent Link: http://hdl.handle.net/11104/0331580