Resonances of the hydrogen atom in strong parallel magnetic and electric fields

The behavior of the rsonances of a hydrogen atom in parallel magnetic and electric fields is obtained with a complex scaling plus B-spline method. The resonant parameters E and Γ₀ in an electric field alone are consistent with those obtained by other methods. In a fixed electric field F the widths {Γ} of both the ground and excited resonances decrease with an increase of the magnetic field B, and the relative variation ({Γ}-Γ₀)/Γ₀ is directly proportional to the ratio of the magnetic-field strength to the electric-field strength. The positions of the resonances, however, are pushed higher by an increasing of magnetic field. The pushing effect is insensitive to the electric-field strength and depends almost entirely on the magnetic-field strength.