Bi-isonicotinic acid on rutile (1 1 0): calculated molecular and electronic structure

Bi-isonicotinic acid adsorption on rutile TiO2(1 1 0) surfaces has been studied using periodic first principles density functional calculations. The geometry of a dissociatively bridge-bonded adsorbate has been optimized, and the influence of the position of the dissociated protons on the surface examined. The results are in agreement with published experimental information on the adsorption geometry. Adsorbate strain is found to reduce the adsorption energy by 40% compared to ideal bridge binding to the surface. The electronic structure of the system is also investigated, including an analysis of the density of states of the valence and conduction bands. The simulated N 1s near-edge X-ray absorption fine structure (NEXAFS) spectrum is essentially in agreement with experiment, but points to problems in the modeling of the experimental conditions.