Hydrogen Molecules In a Superstrong Magnetic Field: II. Excitation Levels

We study the energy levels of H2 molecules in a superstrong magnetic field (B >∼ 1012 G), typically found on the surfaces of neutron stars. The interatomic interaction potentials are calculated by a Hartree-Fock method with multi-configurations assuming electrons are in the ground Landau state. Both the aligned configurations and arbitrary orientations of the molecular axis with respect to the magnetic field axis are considered. Different types of molecular excitations are then studied: electronic excitations, aligned (along the magnetic axis) vibrational excitations, transverse vibrational excitations (a constrained rotation of the molecular axis around the magnetic field line). Similar results for the molecular ion H2 are also obtained and compared with previous variational calculations. Both numerical results and analytical fitting