Nonzero angular momentum states of the helium atom in a strong magnetic   field
  The electronic structure of the helium atom in the magnetic field regime B=0-100a.u. is investigated, using a full configuration interaction approach which is based on a nonlinearly optimized anisotropic Gaussian basis set of one-particle functions. The corresponding generalized eigenvalue problem is solved for the magnetic quantum number M=-1 and for both even and odd z-parity as well as singlet and triplet spin symmetry. Accurate total electronic energies of the ground state and the first four excitations in each subspace as well as their one-electron ionization energies are presented as a function of the magnetic field. Additionally we present energies for electromagnetic transitions within the M=-1 subspace and between the M=-1 subspace and the M=0 subspace treated in a previous work. A complete table of wavelengths and field strengths for the detected stationary points is given. 
Wolfgang Becken and Peter Schmelcher