Nonempirical quantum-chemical calculation of the electric field gradient at the 51V nucleus sites in alkali metavanadates

The electric-field gradient tensor at the vanadium nucleus site was calculated ab initio within a cluster model for chained vanadates XVO3 (X=Li, Na, K). A comparison with experiment showed that it suffices to consider only small (VO4)3− and (V3O10)5− clusters in crystals of this type. The calculation scheme stability with respect to increasing cluster size was analyzed.