Ab initio SCF molecular orbital calculations were conducted at the STO-3G level for an extensive domain of the potential energy surface for the ethylene-hydronium ion complex. The minimal energy species has a relative stability of 20 kcal mol-1, and is held together by a hydrogen that is directed perpendicularly to the center of the double bond. This bonding hydrogen is attached to the oxygen at a distance of 0.07 Å longer than that in the water molecule, with an oxygen-ethylene distance of 2.7 Å. There is a single well in the proton-transfer potential energy curve, the energy rising monotonically as the proton is shifted from oxygen to ethylene. When the ethylene-oxygen distance is extended to 3.1 Å, a double well develops. Perturbations of the equilibrium geometry give evidence of a transient species with a "bifurcated hydrogen bond" of 7 kcal mol-1. Geometries and charge distributions are reported, and the results compared with the corresponding ethylenewater complexes.
ASJC Scopus subject areas
- Condensed Matter Physics
- Physical and Theoretical Chemistry