A New Approach to Calculating the Binding Energy of Molecules from Electron Density by Thermodynamic Formalization

There are many approaches to molecular energy calculations, and there are still no methods to calculate the binding energy of a molecule accurately. Also, in considering molecules, all processes are actually performed at finite temperatures. And the process of molecular formation is a process of increasing the binding energy of a molecule, and if the molecule is considered as a thermodynamic system, it is also possible to think of the physical quantity that determines the direction of the spontaneous process. This paper propose a new approach to calculating the binding energy of a molecule by examining the relationship between the electron density and binding energy and about the thermodynamic formalization of molecule. From the calculated value by Gaussian09w (HF, 6-31g) simulation of 100 molecules of 10 species and the binding energy in some literatures, the correlation was derived and confirmed that two parameters are given for each species. It was found that the binding energy of a water molecule can be calculated, in particular. Also the molecular free energy is conceptualized where the value can be index of molecular formation and molecular optimization process. This theory, together with the potential well theory in quantum mechanics, can serve as a basis for explaining the phenomenon that for molecules with the same chemical structure formula, higher energy molecules exist more stably.