Two-dimensional hydrogenlike atoms in the presence of a magnetic field: Quasifractional approximations

Two-point quasifractional approximations have been used to study the energy levels for a hydrogenic atom when a magnetic field is applied perpendicular to the x-y plane. Perturbation theory gives power-series expansions for weak magnetic fields and asymptotic expansions for very high magnetic fields. Using appropriate forms of the two-point quasifractional approximants, we recover both expansions and have found a better interpolation between the two limiting situations for the ground- and excited-state energies than those previously published