Equilibrium geometries, electron affinities and dissociation energies Of W-2, W-2(-), W-3 and W-3(-) clusters and harmonic vibrational frequencies Of W2 and W2 clusters were studied by density functional methods B3LY-P, B3PW91, BLYP, BHLYP, B3P86 and MPW1PW91. The results indicate that singlet state is the ground state for W-2 cluster, and doublet for W-2(-) cluster. For W-3 and W-3(-) clusters, triplet with D-3h symmetry and doublet with C-2v symmetry are the ground state, respectively. Comparing among different methods, the results indicate that the calculated quantities, such as. electron affinity and dissociation energy, are sensitive to the methods used and cluster size. (C) 2003 Elsevier Science B.V. All rights reserved.