Generalized relativistic variational calculations for hydrogenic atoms in arbitrary magnetic fields

A relativistic basis set composed of products of Slater- and Landau-type functions is introduced and applied to the accurate calculation of the ground-state energy of an electron in a static Coulomb field and a magnetic field of arbitrary strength. The relativistic corrections for strong magnetic fields differ from previous relativistic adiabatic approximations. It is found that the sign of the relativistic correction changes from negative to positive; for hydrogen this occurs near B = 10 to the 11th G. The accuracy of the nonrelativistic-limit results matches or exceeds that of previous nonrelativistic calculations. (Author)