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.
1. In previous versions, parameters α and β were expressed by empirical formulas respectively; In the new version, these parameters are determined by the geometric model. 2. In previous versions, parameter δ was considered to have the meaning of atomic charge; In the new version, parameter δ is the micro variable value of atomic hardness coefficien.