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 …

Benchmark variational calculations of the lowest eight Rydberg 2 P o states of the singly
ionized carbon atom (stable isotopes C+ 12, C+ 13, and C+ 14, as well as the infinite …

Energy levels, normal and specific mass shift parameters as well as electronic densities at
the nucleus are reported for numerous states along the beryllium, boron, carbon, and …

All available experimental data on the spectrum of singly ionized carbon have been critically
analyzed. Measurement uncertainties of all published studies have been reassessed. The …

Benchmark variational calculations of the lowest ten Rydberg S 2 states of two stable
isotopes of the boron atom (B 10 and B 11) are reported. The nonrelativistic wave functions …

We report absolute frequency measurements on the three excited-state transitions
connecting the 2 p 2 (3 P) 3 s 2 P 1/2, 3/2 and 2 p 2 (3 P) 3 p 2 D 3/2, 5/2∘ states in neutral N …

In this work, we report benchmark variational calculations of the five lowest doublet S-states
of the C+ ion. The wave functions of this five-electron system are expanded in terms of 16 …

In this work, we present a series of benchmark variational calculations for the ground and 19
lowest bound excited singlet S and P states of the beryllium atom. The nonrelativistic wave …

Variational calculations have been carried out for the ground states of several members of
the beryllium isoelectronic series using a standard Hylleraas approach involving Slater-type …