Analysis of uv-visible fluorescence following inner-shell excitation of N-2 molecules - art. no. 022513

Light emission induced by inner-shell excitation of N-2 molecules has been investigated in the wavelength region 250 less than or equal to lambda(fluo )less than or equal to 1000 nm. Synchrotron radiation from the SuperACO sto rage ring in Orsay (France) has been used for the photoexcitation and a hig h-resolution secondary monochromator (Delta lambda(fluo) = 0.2 nm) for the spectral analysis of the fluorescence light. Vibrationally resolved molecul ar N-2(+) (B (2)Sigma(u)(+) --> X 2 Sigma(g)(+)) transitions show clearly t he coupling between the (1s-->pi*) core excitation and the ionization of th e (2 sigma(u)) valence electron. The main contribution to the fluorescence spectra stems from excited neutral and excited singly charged atoms produce d by the dissociation of highly excited molecular states. The singly ionize d N+ atoms are produced upon resonant (1s-->pi*) excitation as well as upon excitation to the (1s(-1)-sigma*) continuum resonance. Fluorescence transi tions of the type N+ 1s(2)2s(2)2p4f-->1s(2)2s(2)2p3d as well as 2p3d-->2p3p and 2p3p-->2p3s have been analyzed. The neutral N fragment is found nearly exclusively after excitation of the (1s(-1)-pi*) resonance, and mainly rad iative decay of the N 1s(2)2s2(2)2p(2)3p excited states has been observed. The obtained experimental results represent additional and very detailed in formation on the final states of the molecular dissociation and provide a n ecessary basis for a theoretical treatment of the relaxation processes of i nner-shell excited molecules.