EXAMINATION OF THE PATHWAYS IN THE SOFT-X-RAY (530.8-EV) INDUCED FRAGMENTATION OF O-2 BY ELECTRON-ION COINCIDENCE MEASUREMENTS

Monochromatic synchrotron radiation is used to excite the K-shell electrons of oxygen at the pi*-resonance. Electronic decay and the concomitant fragmentation are examined using coincident electron energy analysis and time-of-flight mass spectrometry. By these means, the production of specific ionic products, observed in time-of-flight mass spectra, are correlated to specific electronic decay channels, identified in the electron energy spectra. It thereby is possible to relate the dissociation products, their kinetic energies, and their electronic configurations to the electronic configuration of the parent molecular ion produced by electronic decay of the core-hole excited state. Such data provide information regarding the energies of electronic states and the stability and potential energy surfaces of singly and multiply charged molecular ions.