Geometric and electronic properties of titanium clusters studied by ultrasoft pseudopotential

The structural and electronic properties of titanium clusters are studied b y the plane-wave ultrasoft pseudopotential method with the generalized grad ient approximation. The equilibrium geometries Ti-n (n = 2-14, 19, 55) clus ters are determined by optimizing the bond length of various structural iso mers under a symmetric constraint. Pentagonal growth patterns are found for small Ti, clusters and the theoretical binding energies are in reasonable agreement with experimental results on Ti-n(+). The electron density of sta te of Ti, clusters shows a rapid convergency towards bulk bands, which agre es with the photoelectron spectra of Ti clusters. (C) 2001 Elsevier Science L,td. All rights reserved.