AbstractA new method is proposed for the analysis of components of molecular interaction energy within the Hartree‐Fock approximation. The Hartree‐Fock molecular orbitals of the isolated molecules are used as the basis for the construction of Fock matrix of the supermolecule. Then certain blocks of this matrix are set to zero subject to specify boundary conditions ...... hiện toàn bộ
AbstractMany‐body (diagrammatic) perturbation theory (MBPT), coupled‐pair many‐electron theory (CPMET), and configuration interaction (CI) are investigated with particular emphasis on the importance of quadruple excitations in correlation theories. These different methods are used to obtain single, double, an...... hiện toàn bộ
AbstractAn approximate fourth‐order expression for the electron correlation energy in the Møller–Plesset perturbation scheme is proposed. It takes into account all the contributions to the fourthorder energy neglecting only those of the triple‐substituted determinants. It is size consistent and correct to fourth order for an assembly of isolated two‐electron system...... hiện toàn bộ
Roberto Dovesi, Roberto Orlando, Alessandro Erba, Claudio M. Zicovich‐Wilson, Bartolomeo Civalleri, Silvia Casassa, Lorenzo Maschio, Matteo Ferrabone, Marco De La Pierre, Philippe D’Arco, Mariella Causa, Michel Rérat, Bernard Kirtman
The capabilities of the Crystal14program are presented, and the improvements made with respect to the previous Crystal09version discussed. Crystal14is anab initiocode that uses a Gaussian‐type basis set: both pseudopotential and all‐electron strategies are permitted; the latter is not much more expensive th...... hiện toàn bộ
AbstractTwo three‐dimensional numerical schemes are presented for molecular integrands such as matrix alements of one‐electron operators occuring in the Fock operator and expectation values of one‐electron operators describing molecular properties. The schemes are based on a judicious partitioning of space so that product‐Gauss integration rules can be used in each...... hiện toàn bộ
T. Kolev, Evelina Velcheva, Bistra A. Stamboliyska, Michael Spiteller
AbstractThe potential energy surface of curcumin [1,7‐bis(4‐hydroxy‐3‐methoxyphenyl)‐1,6‐heptadiene‐3,5‐dione] was explored with the DFT correlation functional B3LYP method using 6‐311G* basis. The single‐point calculations were performed at levels up to B3LYP/6‐311++G**//B3LYP/6‐311G*. All isomers were located and relative energies determined. According to the cal...... hiện toàn bộ