Electron Distributions in Pure TiO$_{2}$ in Anatase Phase and with Hydrogen Impurities*

The electronic structures of pure TiO$_{2}$ in anatase phase and with hydrogen impurity have been investigated by the Hartree-Fock Cluster Procedure. They are used to study the associated $^{47}$Ti and $^{17}$O nuclear quadrupole coupling constants e$^{2}$qQ and asymmetry parameters $\eta $ . For pure TiO$_{2}$ in the anatase phase, comparison will be made with theoretical and experimental e$^{2}$qQ in the rutile phase, the value of $\eta $ for $^{47}$Ti vanishing in the anatase phase due to local axial symmetry. *Supported by US-Nepal Research Program, UGC Nepal, and Senior Fulbright Post-Doctoral Fellowship (S.B.) **Also at UCF, Orlando