The triplet contribution is computed to the 1 and 2 S 0 e 1 states of the He atom, to the 1 S 0
e 1 state of the Li+ and Be 2+ ions, and to the X 1 Σ g+ ground state of the H 2 molecule by …

Abstract The Born–Oppenheimer (BO) approximation is the bedrock of quantum mechanical
calculations of atomic and molecular systems. However, there are effects in these systems …

Variational, nonrelativistic energies have been calculated for the ground state (3 P g) and
the lowest quintuplet state (5 S u) of the carbon atom, with wave functions expressed in the …

Deformed explicitly correlated Gaussian (DECG) basis functions are introduced, and their
matrix elements are calculated. All matrix elements can be calculated analytically in a closed …

An algorithm for quantum-mechanical nonrelativistic variational calculations of L= 0 and M=
0 states of atoms with an arbitrary number of s electrons and with three p electrons have …

In this work we consider an efficient algorithm for variational calculations of quantum few-
particle systems in S, P, and D states of the even parity using all-particle explicitly correlated …

An algorithm for quantum mechanical variational calculations of bound states of diatomic
molecules corresponding to the total angular momentum quantum number equal to one (N …

The order of low-energy states of six-electron harmonium is uncertain in the case of strong
correlation, which is not a desired situation for the model system being considered for future …

An algorithm for optimizing the nonlinear parameters of all-electron explicitly correlated
Gaussian functions is presented. The approach uses the time-dependent variational …

An algorithm for direct non-Born–Oppenheimer quantum mechanical variational calculations
of bound states of binuclear systems with Coulombic interactions corresponding to the total …