Quantum theory of molecular structure

The quantum theory of molecular structure developed here and the standard BO approach rely on the separability between electronic and nuclear configurational degrees of freedom. However, the way this is achieved differs radically between the approaches. In the treatment described here, the nuclei are seen to be trapped by an attractor generated by the stationary electronic wave function (nuclei follow the electronic states ) the electronic wave function does not depend upon the instantaneous positions of the nuclei as early proposed by this author [4] a change of electronic state, characterizing a chemical reaction with reactants and products in their ground electronic states, is described as a Franck-Condon like process. 

The molecular concept has become so central in chemistry that understanding of chemical events is commonly assumed to consist of relating experimental observations to micro events at the molecular level, which means changes in molecular structure. In this sense molecular structure is a fundamental theoretical concept in chemistry. As the micro changes are invariably triggered by electron transfer, the correct theory at the molecular level must be quantum mechanics. It is therefore surprising that a quantum theory of molecular structure has never developed. This failure stems from the fact that physics and chemistry operate at different levels and that grafting the models of physics onto chemistry produces an incomplete picture. 

Parr, R. G., (1963). Quantum Theory of Molecular Structure, W. A. Benjamin, New York. 

L. Lathouwers, P. van Leuven, and M. Bouten, Chem. Phys. Lett., 52,439 (1977). Quantum Theory of Molecular Structure. L. Lathouwers, Phys. Rev. A, 18, 2150 (1978). Generator-Coordinate Theory of Molecular Spectra. 

Bader, R.F.W. (1991) A quantum theory of molecular structure and its applications. Chemical Reviews, 91, 893-928. 

After the discovery of quantum mechanics in 1925 it became evident that the quantum mechanical equations constitute a reliable basis for the theory of molecular structure. It also soon became evident that these equations, such as the Schrodinger wave equation, cannot be solved rigorously for any but the simplest molecules. The development of the theory of molecular structure and the nature of the chemical bond during the past twenty-five years has been in considerable part empirical — based upon the facts of chemistry — but with the interpretation of these facts greatly influenced by quantum mechanical principles and concepts. 

Parr RG. Quantum theory of molecular electronic structure. New York Benjamin, 1963. 

R.G. Parr, The Quantum Theory of Molecular Electronic Structure. A. Benjamin Inc., New York, 1963. 

Approximate calculations of this activation energy have been made in a number of examples using the quantum theory of molecular binding, by making assumptions concerning the structure and partition functions of the transition state molecule. 

The development of theoretical chemistry ceased at about 1930. The last significant contributions came from the first of the modern theoretical physicists, who have long since lost interest in the subject. It is not uncommon today, to hear prominent chemists explain how chemistry is an experimental science, adequately practiced without any need of quantum mechanics or the theories of relativity. Chemical thermodynamics is routinely rehashed in the terminology and concepts of the late nineteenth century. The formulation of chemical reaction and kinetic theories take scant account of statistical mechanics and non-equilibrium thermodynamics. Theories of molecular structure are entirely classical and molecular cohesion is commonly analyzed in terms of isolated bonds. Holistic effects and emergent properties that could... 

LECTURES ON QUANTUM THEORY OF MOLECULAR ELECTRONIC STRUCTURE... 

Jiri Cizek s research program centers on the quantum theory of molecular electronic structure and related developments in quantum chemical methodology, coupled-cluster approaches to many-electron correlation problems,105 large-order perturbation theory,106 dynamical groups and exactly solvable models, lower bounds, and the use of symbolic computation language in physics and in chemistry. 

Parr, R. G. Quantum theory of molecular electronic structure. New York Benjamin 1963 Schaefer III, H. F. The electronic structure of atoms and molecules. A survey of rigorous quantum mechanical results. Reading, Massachusetts Addison-Wesley 1972... 

V.M. Tatevskii. Classical Theory of Molecular Structure and Quantum Mechanics [in Russian] Khimiya, Moscow, 1973. 

W. M. Tatewski, Quantum Mechanics and the Theory of Molecular Structure, Chemie, Weinheim, 1969. 

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