Newns-Anderson model for Chemisorption Bo Hellsing Department of Physics, Göteborg University, Göteborg, SWEDEN Atom Metal

Newns-Anderson model Hamiltonian Vak | a > | k >

and the adsorbate-substrate binding energy - chemisorption energy. We will apply the Hartree-Fock approximation (mean filed approximation). The adsorbate Green's function is obtained which can be used to calculate e.g. electron charge transfer between the adsorbate and the substrate and the adsorbate-substrate binding energy - chemisorption energy. Crusial quantities are the adsorbate-substrate interaction Vak and the coulomb interaction on the adsorbate U. The retarded Green's function has the elements:

We now derive the equation of motion for the Green's functions. We start by taking the time derivative:

Heisenberg: We thus get

Hand-in problem I: We thus get