Non-zero 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 = 0-100 au 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.