Calculation of energies of three-electron systems in a strong magnetic field using Explicitly Correlated Gaussian Basis

Strong magnetic fields can significantly alter the properties of atoms and allow the formation of stable negative ions such as He$^-$. We have calculated the energies of systems comprised of three electrons in the presence of strong magnetic fields by using the Stochastic Variational Method with deformed Explicitly Correlated Gaussian basis.\footnote{J. A. Salas and K. Varga, \textbf{Phys. Rev. A} 89, 052501 (2014)} This approach yields accurate values for three-electron systems and predicts that the He$^-$ ion in a strong magnetic field has stable states, within the non-relativistic framework, in the infinite nuclear mass approximation. The energy spectrum and the properties of three-electron systems as a function of the strength of the magnetic field show the effect of the rivalry between the Coulomb interaction and the magnetic confinement.