Spectrum of neutral helium in strong magnetic fields

We present extensive and accurate calculations for the excited-state spectrum of spin-polarized neutral helium in a range of magnetic field strengths up to 10 G. Of considerable interest to models of magnetic white dwarf stellar atmospheres, we also present results for the dipole strengths of the low-lying transitions among these states. Our methods rely on a systematically saturated basis set approach to solving the HartreeFock self-consistent field equations, combined with an ‘‘exact’’ stochastic method to estimate the residual basis set truncation error and electron correlation effects. We also discuss the applicability of the adiabatic approximation to strongly magnetized multielectron atoms. @S1050-2947~99!02504-4#