The interference effects in the alignment and orientation of the Kr II 4p⁴5p states following Kr I 3d⁹np resonance excitation

The energy dependence of the alignment parameter A₂₀ for the Kr II 4p⁴5p(E ₁J₁) states following excitation in the Raman regime with the exciting-photon energy passing through the Kr I 3d⁹np resonances was investigated theoretically and experimentally. Interference between the resonance and direct photoionization channels explains the dependence of A₂₀ on the excitation energy. Experimentally, A₂₀ was determined after the analysis of 5p–5s fluorescence decay of the 4p⁴5p(E ₁J₁) states excited with monochromatized synchrotron radiation. The band pass of the synchrotron radiation was set to 10 meV which is smaller than the natural width of the 3d⁹np resonances (∼83 meV). Additionally, a strong energy dependence was predicted for the orientation parameter O₁₀ as well as for the angular distribution parameter of photoelectrons, β^e, for several 4p⁴5p(E ₁J₁) ionic states.