Density functional calculation of the growth, electronic and bonding properties of titanium clusters Tin (n=2-20)

The growth, electronic, bonding properties of titanium clusters up to 20 atoms, within the framework of a gradient-corrected density functional theory, are reported. A number of low-lying isomers having different spin multiplicities are identified for each size. The size-dependant growth patterns are the tetrahedral-, octahedral-, icosahedreal- and sixfold icositetrahedral-derived sequences. The compact arrangement results from the covalent metallic bonds. The calculated density of states for the ground states of anionic titanium clusters matches well with the photoelectron spectroscopy. Especially a Z16 Frank-Kasper polyhedron (T-d) is found to be the lowest energy structures of anion Ti-17(-), cluster. The calculations of binding energies, second-order differences in energy, charge densities and highest occupied molecular orbital states as well as vibrational spectra reveal that clusters with n = 7, 13, 15 atoms are magic clusters. (C) 2015 Published by Elsevier B.V.