Effects of exchange, correlation, and numerical approximations on the computed properties of the rutile ${\mathrm{TiO}}_2$ (100) surface

We present fully converged, all-electron, ab initio calculations of the structural relaxation at the ${\mathrm{TiO}}_2\mathrm{}\left(100\right)\mathrm{}-(1\mathrm{}\times 1)$ surface. The effects of electron exchange, correlation, and various numerical approximations are isolated and quantified. We find that the predicted relaxations are insensitive to the treatment of exchange and correlation, but do depend on numerical approximations. The results of previous ab initio calculations are discussed in the light of these findings.