The theoretical calculation of potential energy surfaces
Abstract
Potential energy surfaces calculated using single determinant SCF molecular orbital theory exhibit cusps which arise form the intersection of two surfaces, cusps which do not appear on the exact surface. It is the presence of these cusps which classify reactions on these surfaces as "forbidden" in the WoodwardHoffmann sense. An ambiguity in the WoodwardHoffmann rules exists however, for there are reactions which are forbidden along one reaction path yet are allowed along another path in the same symmetry even when the two paths connect the same reactant and product minima. The question that arises as to when and how the cusp disappears is addressed. To investigate this question, a twoelectron, twoorbital model was constructed and the behavior of SCF single determinant wavefunctions in the vicinity of the cusp was studied. This model supplies the conditions under which a cusp can be terminated and adequately accounts for the apparent ambiguity in the WoodwardHoffmann rules.
 Publication:

Ph.D. Thesis
 Pub Date:
 1978
 Bibcode:
 1978PhDT........15F
 Keywords:

 Chemical Reactions;
 Surface Geometry;
 Surface Properties;
 Analysis (Mathematics);
 Approximation;
 Molecular Orbitals;
 Surface Reactions;
 Atomic and Molecular Physics