K-CO on Transition Metals: A Local Ionic Interaction.
PENNSYLVANIA UNIV PHILADELPHIA DEPT OF PHYSICS
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We wish to address the nature of the K-CO interaction on a transition metal surface when the KCO stoichiometry is approx. 1. The interaction proposed is transfer of the K 4s electron to CO. A BORN-Haber cycle for this process on a surface has been calculated. The reference state is K plus CO, bound separately to the surface a. A key point in the cycle is that removal of the electron from K bound to a metal surface b is less costly in energy approx. metalK surface, i.e. approx. 2.0 eV than from K in the gas phase IP 4.3 eV. This means that the complex is significantly stabilized on the surface. The removed K electron is then transported to the isolated adsorbed CO c at a cost of the electron affinity of CO approx. 1.5 eV. When the isolated ions are brought together d the net stabilization at the equilibrium geometry is approx. - 1.8 eV.
- Inorganic Chemistry