Electronic structure of the silver (1+)-ethylene complex

The electronic structure of the silver (1+)-ethylene complex has been calculated using the nonempirical self-consistent field theory in an extended Gaussian orbital basis set and in a top-complex geometry corresponding to Dewar's original two-way donor-acceptor model. A purely electronic binding energy of just under 1.0 eV is predicted for this complex in the gas phase. For comparison purposes an identical calculation was carried out on ethylene in the presence of a unit point charge replacing the Ag⁺ ion. Based on an examination of core electron binding energies and basis orbital populations it is concluded that (a) the point charge model is capable of describing most of the ethylene intramolecular electron rearrangement in the complex, and (b) the metal olefin σ bond is more important than the π bond. The energy ordering of the excited states of the complex is found to be dominated by the upper orbital energy. A number of considerations and results mitigate against the alternative side complex as the most stable geometric configuration for AgC₂H₄⁺.