The hydrogen atom in very strong magnetic and electric fields

The authors solve the three-dimensional Schroedinger equation for a hydrogen atom in strong magnetic and electric fields of arbitrary mutual orientation and obtain accurate values for the wavelengths and oscillator strengths of low-lying bound-bound transitions. They focus on field strengths relevant to the interpretation of spectra of magnetic white dwarf stars - one of the major applications of these calculations. Various aspects of the influence of the electric field on the calculated spectra are investigated and the results are compared with the diamagnetic hydrogen atom. The authors present results on the dependence of the wavelength shifts, changes in the oscillator strengths with the electric field strength and its relative orientation to the magnetic field, and the emergence of additional anticrossings caused by further symmetry breaking and stationary lines, which provide a direct connection to astrophysical observations