ADSORPTION OF NH3 ON MGO(100) - A COMPARATIVE-STUDY OF AB-INITIO AND SEMICLASSICAL CALCULATIONS

Three ab initio approaches (i.e., molecular Hartree-Fock, periodic crystal Hartree-Fock and embedded perturbed cluster Hartree-Fock) were used to determine the adsorption site and energy of ammonia molecules on an ideal MgO(100) surface. Each approach is discussed by comparing it with previous semi-classical calculations and with data from laser-induced thermal desorption and low-energy electron diffraction experiments. It is shown that the latter two ab initio methods offer complementary information and their results are fairly consistent with the available data.