Production and characterization of thermally-annealed large clusters by high-pressure laser-vaporization technique

We have developed a high-pressure laser-vaporization cluster source, which enables us to produce large, annealed clusters. Large carbon clusters up to C ₂₀₀₀ ⁺ , annealed sodium fluoride clusters of Na⁺(NaF)_n, and ammonium iodide clusters of NH ₄ ⁺ (NH₄I)_n have been produced by this technique. Annealed ammonium iodide clusters show a transition from hydrogen bonded complexes to ionic crystals as the cluster size increases. The characterization of the present technique and the production processes of the large, annealed clusters are discussed.