Effects of exchange, correlation, and numerical approximations on the computed properties of the rutile TiO2 (100) surface

We present fully converged, all-electron, ab initio calculations of the str uctural relaxation at the TiO2(100)-(1 x 1) surface. The effects of electro n exchange, correlation, and various numerical approximations are isolated and quantified. We find that the predicted relaxations are insensitive to t he treatment of exchange and correlation, but do depend on numerical approx imations. The results of previous ab initio calculations are discussed in t he light of these findings. [S0163-1829(99)05003-1].