Density-functional-theory calculations of matter in strong magnetic fields. I. Atoms and molecules

摘要

We present calculations of the electronic structure of various atoms and molecules in strong magnetic fields ranging from B=10(12) G to 2x10(15) G, appropriate for radio pulsars and magnetars. For these field strengths, the magnetic forces on the electrons dominate over the Coulomb forces, and to a good approximation the electrons are confined to the ground Landau level. Our calculations are based on the density functional theory, and use a local magnetic exchange-correlation function which is tested to be reliable in the strong field regime. Numerical results of the ground-state energies are given for H-N (up to N=10), He-N (up to N=8), C-N (up to N=5), and Fe-N (up to N=3), as well as for various ionized atoms. Fitting formulae for the B dependence of the energies are also given. In general, as N increases, the binding energy per atom in a molecule, parallel to E-N parallel to/N, increases and approaches a constant value. For all the field strengths considered in this paper, hydrogen, helium, and carbon molecules are found to be bound relative to individual atoms (although for B less than a few x10(12) G, carbon molecules are very weakly bound relative to individual atoms). Iron molecules are not bound at B less than or similar to 10(13) G, but become energetically more favorable than individual atoms at larger field strengths.