Thermal dissociation of 1,2-dioxethane. II. Quantum topology of the charge distributions

The topological properties of the charge distribution of 1,2-dioxethane along the dissociation path (to formaldehyde products) and in different Hartree–Fock solutions are presented. At the equilibrium geometry of 1,2-dioxethane, all bond paths do not coincide with the corresponding internuclear axes. The outward curvature of the O? O bond path elaborates upon the concept of strain in the dioxethane ring. This weak binding of the ring is further confirmed by the considerably low ρ(r) value at the ring (3, +1) saddle point. An extension of the theory to the dynamic case has been discussed in terms of the topological changes in ρ(r) along the reaction path. The catastrophe of the chemical change, i.e., rupture of the dioxethane ring, takes the form of gradual merging and annhilation of the O? O (3, ?1) and the ring (3, +1) critical points. The values of ρ(r) at the positions of the critical points along the reaction path provide a topological characterization and definition of “partial valence.” The difference between the topological behavior of ρ(r), as obtained by different HF solutions, along the reaction path is analyzed and discussed.