Electron correlation potential energy surfaces

Theoretical chemistry is the discipline that uses quantum mechanics, classical mechanics, and statistical mechanics to explain the structures and dynamics of chemical systems and to correlate, understand, and predict their thermodynamic and kinetic properties. Modern theoretical chemistry may be roughly divided into the study of chemical structure and the study of chemical dynamics. The former includes studies of (1) electronic structure, potential energy surfaces, and force fields (2) vibrational-rotational motion and (3) equilibrium properties of condensed-phase systems and macromolecules. Chemical dynamics includes (1) bimolecular kinetics and the collision theory of reactions and energy transfer (2) unimolecular rate theory and metastable states and (3) condensed-phase and macromolecular aspects of dynamics. 

Many potential energy surfaces have been proposed for the F + FI2 reaction. It is one of the first reactions for which a surface was generated by a high-level ab initio calculation including electron correlation [47]. The... 

These results have been recently confirmed by more elaborate ab initio methods including electron correlation and polarizability functions. Structure [7] (Scheme 6c) is found to be more stable than [9] by only 1.5 kcal mol-1. Structure [8] does not exist as a minimum on the potential energy surface and spontaneously collapses to [7]. 

All stationary point geometries were fully optimized at the HF/6-31G level of theory and characterized by harmonic frequency analysis. Single point energies were evaluated at the MP2/6-31G level to account for the effects of electron correlation. Since experiments were carried out in a relatively low dielectric environment (chlorobenzene solvent), it is likely that the shape of the potential energy surface in the gas phase and solution would be comparable... 

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