The ab initio density matrix renormalization group (DMRG) method has been well-
established and has become one of the most accurate numerical methods for the precise …

The density matrix renormalization group (DMRG) is a powerful method to treat static
correlation. Here we present an inexpensive way to calculate correlation energy starting …

A novel approach to strongly contracted N-electron valence perturbation theory (SC-
NEVPT2) as a means of describing dynamic electron correlation for quantum chemical …

The implementation of multireference configuration interaction (MRCI) methods in quantum
systems with large active spaces is hindered by the expansion of configuration bases or the …

We propose an efficient general strategy for generating initial orbitals for generalized
valence bond (GVB) calculations which makes routine black-box GVB calculations on large …

An optimized implementation of block-correlated coupled cluster theory based on the
generalized valence bond wave function (GVB-BCCC) for the singlet ground state of …

A perturbative correction exploiting natural orbitals and the pair function structure of the
unrestricted Hartree-Fock (UHF) wavefunction is devised. The method offers a simple …

To compute the electronic excitation energies, a state-specific multireference Møller–Plesset
perturbation theory (SSMRPT) with a complete active space configuration interaction …

The state-specific multireference perturbation theory (SSMRPT) with an improved virtual
orbital complete active space configuration interaction (IVO-CASCI) reference function …

Block effective Hamiltonian theory (BEHT) is presented in this work. Configuration
interaction functions are divided into P, Q, and R spaces. Effective Hamiltonian is …