EMBEDDED DENSITY-FUNCTIONAL APPROACH FOR CALCULATIONS OF ADSORPTION ON IONIC-CRYSTALS

We present an embedded density functional approach to study adsorption on crystalline surfaces. Following ideas suggested by Cortona, Wesolo wski, and Warshel, we divide the total system into a quantum cluster a nd the surrounding lattice whose density is assumed to be the same as in the ideal crystal. In this case the Kohn-Sham Hamiltonian for elect rons in the cluster contains additional terms corresponding to the Cou lomb, exchange, correlation, and ''nonadditive kinetic energy'' potent ials from the environment. Test calculations for the He and Ar dimers, X-H2O molecular complexes (X=Li+, Na+, K+, F- or Cl-) and water adsor ption on the (001) surface of the NaCl crystal suggest that this model provides a promising alternative for cluster models employed earlier for calculations of defects and adsorption on ionic crystals. (C) 1996 American Institute of Physics.