Reactivity of the (M = Mo, W) cluster with CO and NH3 in the gas-phase: An experimental and DFT study

Gas-phase M x S y + (M = Mo, W) cluster ions were generated by reactive sputtering using a magnetron cluster source. Adsorption of CO and NH3 were used to confirm the stoichiometry of the more prominent M x S y + (M = Mo, W) clusters. For the most abundant M 4 S 6 + cluster, the adsorption experiments are consistent with a calculated structure in which the metal atoms are arranged in an internal tetrahedron surrounded by bridging S-atoms. Binding energies for the consecutive addition of CO and NH3 were also calculated and found to be consistent with the observed cluster adduct stability.