Dissociative single and double photoionization with excitation between 37 and 69 eV in N-2

Dissociative single and double photoionization of N-2 as a function of the exciting-photon energy has been investigated using monochromatized synchrot ron radiation in the exciting photon energy range between 37 and 69 eV by d ispersed VUV fluorescence spectroscopy (80 nm less than or equal to lambda fl less than or equal to 200 nm). Relative partial emission cross sections for N I and N II fluorescence have been recorded as a function of the excit ing-photon energy. There is strong evidence that the precursors of dissocia tive single ionization with one of the fragments being excited are the N-2( +) 2 sigma(g)(-1) (2)Sigma(g)(+) state with its closely lying correlation s tares only. An approximately linear excess energy dependence of the cross s ections for the molecular double photoionization into the N-2(2+) D (1)Sigm a(u)(+) state has been observed in the excitation spectrum of D (1)Sigma(u) (+) --> X (1)Sigma(g)(+) fluorescence in N-2(2+) close to its threshold. Ev idence for dissociative double photoionization with excitation has been fou nd.