Nakatsuji proposed a conceptual force model, called ESF (electrostatic force) model for molecular geometries and chemical reactions. The Hellmann-Feynman theorem (electrostatic theorem) states that the force acting on the nucleus A is the vector sum of the repulsive electrostatic forces due to the other nuclei B in the molecule and the attractive forces exerted on the nucleus A from the negatively charged electron cloud of the molecule.
The ESF model predicts the molecular geometry and the course of the chemical reaction by considering the vector sum of these forces on the constituent nuclei.
- Electrostatic Force Theory for a Molecule and Interacting Molecules I. Concept and Illustrative Applications, H. Nakatsuji, J. Am. Chem. Soc., 95(2), 345 (1973).
- Force Models for Molecular Geometry, H. Nakatsuji and T. Koga, in The Force Concept in Chemistry, B. M. Deb, Ed. (Van Nostrand Reinhold, New York,1981), Chap.3, pp. 137-217.
- Common Natures of the Electron Cloud of the System Undergoing Change in Nuclear Configuration, H. Nakatsuji, J. Am. Chem. Soc., 96(1), 24 (1974).
- Force in SCF Theories, H. Nakatsuji, K. Kanda, and T. Yonezawa, Chem. Phys. Lett., 75(2), 340 (1980).
- Force in SCF Theories. Second Derivative of Potential Energy, H. Nakatsuji, K. Kanda, and T. Yonezawa, J. Chem. Phys., 77, 1961 (1982).