An experimental set-up for generation and characterization of metal clusters

Abstract

An experimental facility has been designed, fabricated and installed for the production and mass characterization of metal clusters. The metal clusters can be produced in a flow tube reactor by laser vapourisation of target metals and characterized by an indigenously designed and fabricated time of flight mass spectrometer (TOFMS). This set-up can be used to carry out a variety of size-dependent physico-chemical properties of metal clusters in gas-phase, viz., stability pattern, ionization potential, fragmentation behaviour and chemical reactivity, etc. The performance of the mass spectrometer has been tested by ionizing different organic molecules like aniline, acetone, benzene, diethyl ether, etc ., using third harmonic (355nm) of Nd:YAG laser. The resolution of this TOFMS is ~500.Vapourisation of Fe target in the flow tube reactor results in the monomer signal of Fe atoms, which reduces on addition of ethylene indicating the reaction of ethylene molecules with Fe atoms. Nano-sized Fe and Al metal particles have been deposited on silicon using this machine and characterised by scanning electron microscopy.