KINETIC-ENERGY STUDY OF THE ION FRAGMENTS PRODUCED BY DISSOCIATIVE PHOTOIONIZATION OF NITRIC-OXIDE

The kinetic energy distribution spectra of the ion fragments N+ and O produced by dissociative photoionization of NO and the dissociative p hotoionization efficiency curve for the ion fragments with specific ki netic energies are observed at photon energies from 19 to 60 eV. Three groups of N+ fragments are observed with their kinetic energies cente red at 0, 0.32 and 1.1 eV, respectively. The two groups of energetic N + fragments correspond to the predissociation of the c(3) Pi and B'(1) Sigma(+) states of NO+, respectively. These two states are found to p redissociate primarily into N+(P-3) + O(P-3). Shape resonances are fou nd for the c(3) Pi and B'(1) Sigma(+) states centered at about 28.7 an d 29 eV respectively. The O+ fragments are found to have a continuous kinetic energy distribution concentrated in the region from O to 0.6 e V. The dissociations proceeded mainly through the vibrational levels o f the ionic states of NO leading to N+(P-3) + O(P-3). By use of the un dispersed synchrotron radiation, the O- fragment is found to have a co ntinuous kinetic energy distribution concentrated from 0 to 2 eV. (C) 1997 Elsevier Science B.V.