The variational method complemented with the use of explicitly correlated Gaussian basis
functions is one of the most powerful approaches currently used for calculating the …

Since the early work of Hylleraas on the helium atom, 1 it has been common knowledge that,
to accurately account for the interaction between the electrons in an atom or a molecule …

Nonrelativistic energies for the low-lying states of lithium are calculated using the variational
method in Hylleraas coordinates. Variational eigenvalues for the infinite nuclear mass case …

We report spectroscopic results on the 2 s 2 p P 1 1 state in neutral atomic beryllium-9. The
absolute frequency for the center of gravity is determined to be 42 565.4501 (13) cm-1, a …

The total energies of 28 bound S, P, D, F, G, H, and I states in the three-electron Li atom and
Be+ ion, respectively, are determined with the use of the configuration interaction (CI) with …

Numerical projection methods are elaborated for the calculation of eigenstates of the non-
relativistic many-particle Coulomb Hamiltonian with selected rotational and parity quantum …

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 …

The chemical formula theory (CFT) proposed in Paper I of this series [H. Nakatsuji et al., J.
Chem. Phys. 149, 114105 (2018)] is a simple variational electronic structure theory for atoms …

Accurate quantum-mechanical nonrelativistic variational calculations are performed for the
nine lowest members of the 2 P o Rydberg series (1s 2 np 1, n= 2,…, 10) of the lithium atom …

Very accurate variational non-relativistic calculations are performed for four higher Rydberg
2 D states (1s 2 nd 1, n= 8,…, 11) of the lithium atom (7 Li). The wave functions of the states …