POTENTIAL-ENERGY SURFACE OF THE 1 1 ACETONE IODINE MOLECULAR-COMPLEX AT THE SCF AND MP2 LEVELS/

The ab initio potential energy surface of the 1:1 acetone-iodine compl ex was investigated using valence double-zeta basis sets and effective core potentials. The geometry of the complex was optimized at the SCF and MP2 levels. The most stable geometry is the structure in which th e iodine molecule is collinear with the angle theta (142-degrees for t he geometry optimized at the SCF level, and 131-degrees at the MP2 lev el) to the C-O bond of acetone. The angular difference shows that elec tron correlation is not negligible in the structure of this molecular complex. The potential is described as a double-minimum-like potential with a barrier height of 1.2 kcal mol-1 at the MP2 level. Charge redi stribution analysis of the MP2 potential energy surface showed that th e charge transfer from acetone to iodine was a maximum at the minimum energy.