In this work we consider explicitly correlated complex Gaussian basis functions for expanding the wave function of an N-particle system with the L=1 total orbital angular momentum. We derive analytical expressions for ...

We have performed very accurate quantum mechanical calculations of the five lowest S states of the beryllium atom. In the nonrelativistic part of the calculations we used the variational method and we explicitly included ...

More accurate variational calculations of the lowest three pure vibrational states v=0,1,2 of the 4HeH+ molecular ion have been carried out without assuming the Born-Oppenheimer approximation. In the calculations we ...

Very accurate electron affinity EA calculations of 6Li and 7Li and Li have been performed using explicitly correlated Gaussian functions and a variational approach that explicitly includes the nuclear motion in the ...

We present very accurate quantum mechanical calculations of the three lowest S-states 1s22s2 1S0 , 1s22p2 1S0 , and 1s22s3s 1S0 of the two stable isotopes of the boron ion, 10B+ and 11B+. At the nonrelativistic level ...

A theoretical ab initio approach for calculating bound states of small atoms is developed and implemented. The approach is based on finite-nuclear-mass [non-Born-Oppenheimer (non-BO)] nonrelativistic variational calculations ...

Very accurate quantum mechanical calculations of the first five vibrational states of the 4He3He+ molecular ion are reported. The calculations have been performed explicitly including the coupling of the electronic ...

We review a recent development in high-accuracy non-Born–Oppenheimer calculations of atomic and molecular systems in a basis of explicitly correlated Gaussian functions. Much of the recent progress in this area is due ...

In this work we report variational calculations of the two lowest vibrational states of the HD molecule within the framework that does not assume the Born-Oppenheimer BO approximation. The nonrelativistic energies of ...

Very accurate non-Born–Oppenheimer variational calculations of the ground state of e1LiH have been performed using explicitly correlated Gaussian functions with preexponential factors dependent on powers of the internuclear ...