We optimized structures of vanadium microclusters using the all-electron mixed basis approach. We calculate vanadium two to six with the local density approximation. It has been already known that V₄ is stable on equilateral tetrahedron. The unit cell is chosen as a cube of 0.7nm width. The number of plane waves is 1419. The cutoff energy for PWs is chosen as 11.8 Ry.
The result of calculation for vanadium four is shown in Fig. 1. Here, the abscissa is the bond length and the ordinate is the total energy. The total energy calculation has the minimum at about 0.221nm bond length. This value is close to 0.211/0.227nm that is calculated with LSDA^*1. Now we are calculating molecules consisting of six and more vanadium atoms.

Fig.1. Total energy of vanadium four vs bond length.

^*1 : J. Phys.: Condens. Matter 9(1997) 10739-10748