2022/04/05 by Daria Drwal, Pavel Beran, Drwal, Daria +12
Chemistry · Engineering · Mathematics · Physics and Astronomy · #Ab initio #Adiabatic process #Advanced Chemical Physics Studies #Chemical Physics (physics.chem-ph) #Chemistry #Cholesky decomposition #Complete active space #Connection (principal bundle) #Density matrix renormalization group #Electron #Electronic correlation #Excited state #FOS: Physical sciences #Mathematics #Molecular Junctions and Nanostructures #Perturbation theory (quantum mechanics) #Physics #Quantum mechanics #Renormalization group #Singlet state #Spectroscopy and Quantum Chemical Studies #Strongly Correlated Electrons (cond-mat.str-el) #Wave function #cond-mat.str-el #physics.chem-ph
paper · pdf · doi:10.48550/arxiv.2204.02340
published in arXiv (Cornell University) (Cornell University)
arxiv created 2022/04/05 · openalex publication_date 2022/04/05 · arxiv updated 2022/04/06 · openalex created_date 2022/05/05 · openalex updated_date 2026/07/28
Strong correlation can be essentially captured with multireference wavefunction methods such as complete active space self-consistent field (CASSCF) or density matrix renormalization group (DMRG). Still, an accurate description of the electronic structure of strongly correlated systems requires accounting for the dynamic electron correlation, which CASSCF and DMRG largely miss. In this work a new approach for the correlation energy based on the adiabatic connection (AC) is proposed. The AC\rm n method accounts for terms up to the desired order n in the coupling constant, is rigorously size-consistent, free from instabilities and intruder states. It employs the particle-hole multireference random phase approximation and the Cholesky decomposition technique, which leads to a computational cost growing with the fifth power of the system size. Thanks to AC\rm n depending solely on one- and two-electron CAS reduced density matrix, the method is much more efficient than existing ab initio dynamic correlation methods for strong correlation. AC\rm n affords excellent results for singlet-triplet gaps of challenging organic biradicals. Development presented in this work opens new perspectives for accurate calculations of systems with dozens of strongly correlated electrons.