arXiv subjects
Publications and source records attributed to Oleg Gritsenko.
We construct a strongly regular graph with the parameters (65; 32; 15; 16). The idea is to search for an adjacency matrix that consists of circulant blocks. Equations with such matrices can be reduced to congruences with polynomials matrices of smaller orders. We can consider these congruences over different moduli for a more efficient computational approach.
A combined density and first-order reduced-density-matrix (1RDM) functional method is proposed for the calculation of potential energy curves (PECs) of molecular multibond dissociation. Its 1RDM functional part, a pair density functional, efficiently approximates the ab initio pair density of the complete active space self-consistent-field (CASSCF) method. The corresponding approximate on top pair density Π is employed to correct for double counting a correlation functional of density functional theory (DFT). The proposed ELS-DMΠDFT method with the extended Löwdin-Shull (ELS) 1RDM functional with dispersion and multibond (DM) corrections augmented with the ΠDFT functional closely reproduces PECs of multibond dissociation in the paradigmatic N_2 , H_2O, and H_2CO molecules calculated with the recently proposed CASΠDFT (CASSCF augmented with a Π based scaled DFT correlation correction) method. Furthermore, with the additional M-correction, ELS-DMΠDFT+M reproduces well the benchmark PEC of the N_2 molecule by Lie and Clementi.