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{sup 12} 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 Hartree-Fock self-consistent field equations, combined with an {open_quotes}exact{close_quotes} 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. {copyright} {ital 1999} {ital The American Physical Society}