Dissociative single and double photoionization with excitation between 37 and 69 eV in N2

Dissociative single and double photoionization of N 2 as a function of the exciting-photon energy has been investigated using monochromatized synchrotron radiation in the exciting-photon energy range between 37 and 69 eV by dispersed VUV fluorescence spectroscopy (80 nm fl 200 nm). Relative partial emission cross sections for N I and N II fluorescence have been recorded as a function of the exciting-photon energy. There is strong evidence that the precursors of dissociative single ionization with one of the fragments being excited are the N 2 + 2 g -1 2 g + state with its closely lying correlation states only. An approximately linear excess energy dependence of the cross sections for the molecular double photoionization into the N 2 2+ D 1 u + state has been observed in the excitation spectrum of D 1 u + X 1 g + fluorescence in N 2 2+ close to its threshold. Evidence for dissociative double photoionization with excitation has been found.