Stability trends and fragmentation patterns of gaseous yttrium oxide clusters studied by fast atom bombardment tandem mass spectrometry

Ishenkumba A. Kahwa, Louisiana State University
Joel Selbin, Louisiana State University
Thomas C.-Y. Hsieh, Louisiana State University
David W. Evans, Louisiana State University
Krishna M. Pamidimukkala, Louisiana State University
Roger Laine, Louisiana State University

Abstract

The fragmentation patterns of yttrium oxide cluster species YO+, Y2O2+, Y2O3+, Y3O4+, Y4O6+, Y5O7+, Y6O8+ and Y7O10+ were investigated at collision energies 30-110 and 170 eV by fast atom bombardment tandem mass spectrometry. The collision activated dissociation (CAD) spectra obtained revealed higher thermodynamic stability for the clusters of general formula YαO(3α-1)/2+, where a is an odd number (e.g. YO+, Y3O4+, Y5O7+, Y7O10+) which are also the preferred CAD products for all oxide clusters studied. These most stable oxides are constituted by trivalent yttrium only whereas those containing formally tetravalent yttrium YaO3a/2+, (where a is even) e.g. Y2O3+ and Y4O6+, are extremely unstable. The clusters YaO(3a-2)/2+, (where a is even) containing divalent yttrium, e.g. Y2O2+ and Y6O8+, have considerable stability but their CAD products are again the thermodynamic products YaO(3a-1)/2+. Electronic structures appear to have overriding significance in determining the thermo- dynamic stabilities of the oxide cluster species. © 1988.