AU(N)+-INDUCED DECOMPOSITION OF N2O

Reactions between small gold cluster ions, Au1-4+, and N2O were studied in a Penning trap mass spectrometer. Gold clusters were produced by laser vaporization and injected into a Penning trap. After reaction times of 50-7000 ms the products were detected by time-of-flight mass spectrometry. For the major reaction channel, Au1,2+ + N2O --> Au1,2 N + NO+, rates of (0.9+/-0.1) x 10(-12) cm3 s-1 and (2.4+/-0.4) x 10(-12) cm3 s-1 were determined which are about a factor 500 below the collision rate. The corresponding activation energies for N2O decomposition were estimated to lie below 0.6 eV and 0.3 eV. Additional products with small branching ratios were detected, viz. the ions Au1O+, Au1N2O+, Au2N+, Au2NO+, Au2N2O+, Au3O+, Au3N2O+, and Au4N2O+. This indicates a preference for nitrogen-oxygen bond rupture in the case of Au1+ and Au3+, and for nitrogen-nitrogen bond rupture in the case of Au2+.