A model for electronic structure of VO2

In order to examine the metal-insulator transition in vanadium dioxide (VO2) a number of numerical calculations have been made which attempt to place a chemical emphasis on the understanding of this phenomenon. Angular overlap model (ADM) calculations have been applied to VO6 8- octahedra in the distorted and rutile phases to show the energies and characters of the perturbed V 3d orbitals. These results have then been used to construct Coulson-Fischer-type wavefunctions to model the effects of V-V bonding along the c axis. Calculations have been made on both V-V dimers and V-V chains, using complete neglect of differential overlap (CNDO)- and intermediate neglect of differential overlap (INDO)-type approximations to show the effects on the occupation of the V 3d orbitals of changing the lattice and electron correlation.