Small (Poly)Unsaturated Oxygen Containing Ions and Molecules: A Brief Assessment of Their Thermochemistry Based on Computational Chemistry

The CBS-QB3, CBS-APNO and Gaussian-3 model chemistries have been used to determine the ionic and neutral heats of formation and the adiabatic ionization energies (IE(a)) derived therefrom, for the ca 30 principal isomers of the C(3)H(2)O(*+) and the C(4)H(4)O(*+) families of radical cations. Theory and experiment are in excellent agreement for those molecules whose experimental IE(a) has been accurately measured. In contrast, large deviations …