TRIPLY-IONIZED B2 MOLECULES FROM A TANDEM ACCELERATOR

Beams of B-10(2)3+, B-11(2)3+, and B-10B-11(3)+ ions have been observed to emerge from a tandem accelerator. B2- molecules were injected into the accelerator, and positive ions emerging from the machine were analyzed for mass per charge and total energy. For B-10B-11, intensities of singly-, doubly-, and triply-charged molecules were measured as a function of N2 gas pressure in the accelerator terminal stripper canal. These intensities were found to exhibit the same qualitative behavior for all charge states, with the number of triply-charged molecules a factor of approximately 2 x 10(-4) less than for the double-charge molecules. No quadruply-ionized molecules were seen. The observation of particles corresponding to the breakup products of the multiply-ionized molecules indicates that these species were decaying in flight, and are apparently metastable with lifetimes of approximately mu-s. Comparisons are made between these observations and molecular orbital calculations.