Laser ablation-molecular beam (LAMB) method: coordination (solvation) chemistry of monopositive metal ions in the gas phase

Abstract

The coordination (solvation) chemistry of monopositive metal ions in the gas phase was studied using the laser ablation-molecular beam (LAMB) method. In this method, monopositive metal ions are prepared in the gas phase by laser ablation of metal substrate in vacuum, and allowed to react with molecules or clusters in a molecular beam injected nearby. From the distribution of complex ions obtained, we can deduce useful information on the coordination (solvation) number and/or preferential coordination (solvation) of monopositive metal ions in the gas phase. For reactions with ammonia clusters, intensity gaps are found in the distributions of complex ions obtained. They are intrinsic to each metal ion and indicate the coordination (solvation) number of ammonia ligands in the first coordination (solvation) sphere. For reactions with ammonia-water binary clusters, the distributions of the mixed-ligand complex ions obtained reveal another important aspect, i.e. competitive coordination (solvation). While Mg + and Al + are relatively non-selective, Mn + and Co + are highly selective in the coordination (solvation) with ammonia and water molecules. The third type of competitive coordination, “magic-number-like”, is found for reaction with ammonia-methanol and methanol-water clusters.