Structures of the small Tin (n = 2-5) clusters: A DFT study

A density functional method BPBE with pseudo-potential basis set CEP-121G is selected from different DFT methods to study Tin (n = 2-5) clusters. The stable geometries with different spins are determined. Ti dimer has a ground 3Δg state with bond length of 1.943 Å. The ground state structure of Ti trimer is an isosceles triangle (C2v). For Ti tetramer and pentamer, the ground state structures are distorted tetrahedron (D2d) and triangular bipyramid (C2v), respectively. For the ground states of Ti2−5 clusters, the natural bond orbital analysis is performed, and then we find the distribution of the unpaired electrons. Our results also show that the 4s orbital hybridizes with the 3d orbital. For the ground states, the vibrational spectra are gotten and the vibrational modes corresponding to the maximal IR peaks are determined.