states of small atoms using explicitly correlated Gaussian basis function*

In the framework of the Ritz variational method, we have implemented a new approach for calculating nonrelativistic energies and wave functions of few-electron atomic systems in states with dominant electron configurations containing two p-electrons or a single d-electron. In this approach we employed all-electron explicitly correlated Gaussian basis functions with prefactors in the form of bipolar harmonics. It allows to perform high accuracy calculations of both the ground and excited states, including the Rydberg series of states with n>10. The approach can also be extended to other quantum few-body systems such as small molecules, systems containing exotic particles, etc. We validated the new implementation by carrying out several benchmark calculations of P^e and D states of the boron and carbon atoms and obtained the most accurate non-relativistic energies of these states to date.  The generated wave function can then be used to evaluate leading relativistic and QED corrections, further improving the accuracy of theoretical calculations of atomic spectra.