Fluorescence excitation function of Ni 1200‐Å and cross sections for fluorescence photon‐photoion coincidence produced through photoexcitation of N2

Abstract

The absolute fluorescence excitation function of the Ni 1200‐Å emission through photoexcitation of N2 has been measured in the 250‐620 Å region using synchrotron radiation as the continuous tunable light source. The dissociative photoionization excitation of N2 involving the production of Ni 1200‐Å emission and N+ ion has also been studied at several selected photon wavelengths shortward of 360 Å using a coincidence technique to detect the Ni 1200‐Å fluorescence photon and the N+ ion. The maximum quantum yields for producing these processes are of the order of 6 × 10−2. It was found that dissociative excitation processes can be competitive with the dissociative ionization excitation processes for the multiple‐electron transition states. The present results suggest that the electronic states of N2 in the 320‐340 Å region consist of both ion states of N2+ (Langhoff et al., 1981) and neutral states of N2, which could be the Rydberg states converging to N2++ (Sambe and Ramaker, 1986).