Ground state structures of neutral and charged Ti clusters containing 2 to 16 atoms

By using a simulated-annealing technique with a tight-binding molecular-dynamics, optimized structures of neutral and positively- and negative-charged Ti clusters are determined for the number of atom n = 2-16. It is found that the clusters with the sizes of n = 7,9,13 and 15 are specifically stable compared to those with the other sizes. These magic numbers agree well with the experimental results of time of flight mass spectrometry and collision induced dissociation with Xe. The physical origin of the magic numbers is discussed.