Structure of matter in strong magnetic fields

We give a detailed presentation of Hartree-Fock calculations of atoms and molecular chains in ${10}^{12}$ G magnetic fields, as are supposed to exist on the surface of neutron stars. These calculations are the first self-consistent ones treating exchange properly for atoms heavier than helium in high fields. We find that the isolated atom is energetically favored over molecular chains for Z>2 at fields greater than 1×${10}^{12}$G and for Z>4 at fields greater than 5×${10}^{12}$ G. These results indicate that matter on the surface of neutron stars is bound very weakly, if at all.