The binding of the noble metal cations Au+ and Ag+ to propene

The binding energies for the reaction M+ + CH2CHCH3 → M+[CH2CHCH3], for M = Ag, Au, are predicted using both second order perturbation theory (MP2) and coupled cluster theory (CCSD(T)). Systematically improving the quality of the atomic basis set to the complete basis set limit produces a monotonic improvement in the predicted binding energy for M = Ag relative to the experimentally determined value; the final predicted binding energy is within experimental error. Conversely, the same systematic improvement in the atomic basis set results in successively worse agreement at the MP2 level of theory.