Vibrationally resolved partial cross sections and asymmetry parameters for nitrogen K -shell photoionization of the N2 O molecule

We have measured the vibrationally resolved partial cross sections σ (v1′, v2′, v3′) and asymmetry parameters β (v1′, v2′, v3′) for Nc and Nt K -shell photoionization of the N2 O molecule in the σ* shape resonance region above the Nt and Nc K -shell ionization thresholds. Nc K -shell photoionization of the N2 O molecule predominantly causes the excitation of the quasisymmetric vibrations (v1′), whereas Nt K -shell photoionization causes both quasisymmetric and quasiantisymmetric vibrations (v1′ and v3′) to be excited. The shape resonance energy in the Nc K -shell photoionization increases with an increase in v1′. The β (v1′, 0,0) curves for the Nc K -shell photoionization exhibit maxima at energies close to the shape resonance energies for the individual values of v1′. The shape resonance energy in the Nt K -shell photoionization decreases with an increase in v1′ and slightly increases with an increase in v3′. The β (v1′, 0,0) curves show a significant state dependence in the region of the shape resonance, with the curves shifting to lower energy as v1′ increases. The vibrational state dependence of the cross sections σ (v1′, v2′, v3′) and asymmetry parameters β (v1′, v2′, v3′) are well reproduced by the theoretical calculations using the multichannel Schwinger configuration interaction (MCSCI) method, including both the Nc and Nt ion states.