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 N2O molecule in the σ* shape resonance region above the Nt and Nc K-shell ionization thresholds. Nc K-shell photoionization of the N2O 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.
2007. Vol. 76, no 1, 012506- p.