Cassini-oval description of atomic binding: a new method to evaluate atomic hardness

This paper reports that the binding process of two heteronuclear atoms can be described by Cassini oval in dynamic form, every molecular state corresponds to one of these graphs. the approach is based on a constraint rule between hardness and deformation of atomic particles, then the critical phenomena of molecular deformation are discovered and the calculated potential energy at the critical point is consistent with the experimental dissociation energy of molecules, the new scale uses atomic hardness coefficient as a dimensionless quantity, which accurately reproduces the molecular energies.