COLLISION-INDUCED DISSOCIATION OF TI-N(+) (N=2-22) WITH XE - BOND-ENERGIES, GEOMETRIC STRUCTURES, AND DISSOCIATION PATHWAYS

The kinetic energy dependence of the collision-induced dissociation (CID) of Ti(n)+ (n = 2-22) with Xe is studied by using a guided ion beam mass spectrometer. Examination of the CID cross section behavior over a broad collision energy range demonstrates that Ti(n)+ clusters dissociate exclusively by sequential loss of Ti atoms. Bond energies of ionic titanium clusters D0(Ti(n-1)+-Ti), are determined from measurements of the CID thresholds. D0(Ti(n-1)+-Ti) are found to change significantly as a function of cluster size, with local maxima at n = 7, 13, and 19. This pattern of highly stable cluster ions suggests that titanium cluster ions favor icosahedral structures.