Ab initio Calculations of Electric Field Gradients for Transition Metal Impurities in TiOz *

We present ab initio calculations of E F G s at impurities in a T i 0 2 crystal. They are directly calculated f rom the self consistent charge distribution which is determined by the K K R method within the muffin-tin approximation and based on the local density approximation. Impurities in the crystal are simulated by the super-cell method. Considering the charge state of Sc, Ti, Nb, Cd, Ta impurities in the T i 0 2 , the experimental values were well reproduced. The electronic structure of these impurities is discussed by analyzing the calculated density of states.