Self-consistent field method quantum mechanical

Hybrid quantum mechanics/molecular dynamics (method) Self-consistent field (method)... 

Thdry, V., Rinaldi, D., Rivail, J.-L., Maigret, B., and Ferenczy, G. G. 1994. Quantum Mechanical Computations on Very Large Molecular Systems The Local Self-consistent Field Method , J. Comput. Chem., 15, 269. 

V. Thery, D. Rinaldi, J. L. Rivail, B. Maigret and G. G. Ferenczy, Quantum-mechanical computations on very large molecular-systems - the local self-consistent-field method, J. Comput. Chem., 15 (1994) 269-282. 

The Hiickel molecular orbital (HMO) model of pi electrons goes back to the early days of quantum mechanics [7], and is a standard tool of the organic chemist for predicting orbital symmetries and degeneracies, chemical reactivity, and rough energetics. It represents the ultimate uncorrelated picture of electrons in that electron-electron repulsion is not explicitly included at all, not even in an average way as in the Hartree Fock self consistent field method. As a result, each electron moves independently in a fully delocalized molecular orbital, subject only to the Pauli Exclusion Principle limitation to one electron of each spin in each molecular orbital. 

Looking at the history of correlation from the fifties to the seventies, one may be led to ask whether correlation has been a scientific fashion or a real problem. Twenty years ago, almost everybody seemed to accept the idea that the simple molecular orbital method (MO) must be completed by configuration interaction (Cl), in order to obtain reliable prediction for the physical properties of atoms and molecules. Ten years ago, electron correlation was considered as the central problem of Quantum Chemistry (7). Nowadays, about 90% of the quantum-mechanical calculations on molecules are performed by the self-consistent-field method (SCF) using more or less extended sets of basis functions, without any consideration of the possible effects of correlation. 

The anomalous dispersion effect is associated with the ejection of photoelectrons from inner shell electrons in an atom. The normal scattering describes the interaction of all the electrons in the atom with the X-ray beam. The radial distribution of the electrons in an atom can be calculated using quantum mechanics, originally by Hartree s self-consistent field method (Hartree 1933). In figure 9.12 this distribution is given for rubidium, which has a K edge at 0.8155 A the mean radius for... 

The Englishman, Hartree (1,60) the Russian, Fock (2,3) and the American, Slater (5-7), in the early development of modern quantum mechanics, pioneered the calculation of atomic electronic structure. Hartree based his method on the variation principle and this led naturally to the development of the self-consistent field method, which is at the heart of the design of modem molecular orbital programs. 

The self-consistent field method was introduced in many-electron quantum mechanics by D. R. Hartree in Proc. Camb. Phil Soc. 24, 105 (1928), and his ideas spawned an intensive development, particularly by J. C. Slater and V. Fock. 

The standard way of treating conjugated systems using the o-n separation approximation in the 1930s and into the 1960s was the so-called Hiickel methody In this method, the electron-electron interactions are not explicitly considered. Rather, the positions of the nuclei are fixed, and the electrons move in the field of the nuclei. Much of the error that results from neglecting the interactions of the electrons with one another can be circumvented with proper adjustment of empirical parameters. These parameters are also adjusted to allow (approximately) for the interaction from the o system, which is thus taken into account without specific calculations. This method is crude but does often give qualitative results that enable rationalization of many chemical phenomena of interest. It was a powerful and useful tool in its time. A better approximation is the Hartree-Fock or self-consistent field (SCF) method in which the electron-electron interactions are explicitly considered (Self-Consistent Field Method in Chapter 3). The quantum mechanical calculations on the n system in this case are carried out in a... 

Abstract Hybrid methods, combining the accuracy of Quantum Mechanics and the potency of Molecular Mechanics, the so-called QM/MM methods, arise from the desire of theoretician chemists to study electronic phenomena in large molecular systems. In this contribution, a focus, on the Physics and Chemistry on which theses methods are based on, is given. The advantages, flaws, and limitations of each type of methods are exposed. A special emphasis is put on the Local Self-Consistent Field method, developed in our group. The latest developments are detailed and illustrated by chosen examples. 

Monari A, Rivail J-L, Assfeld X (2013) Theoretical modelling of large molecular systems. Advances in the local self consistent field method for mixed quantum mechanics/molecular mechanics calculations. Acc Chem Res 46 596-603... 

The Non Empirical Local Self Consistent Field Method Application to Quantum Mechanics/Molecular Mechanics (QM/MM) Modeling of Large Biomolecular Systems... 

In this paper we present an overview of the various strategies developed to insert a quantum computation on the chemically active part of a large system into a molecular mechanical description, leading to the so-called QM/MM approaches, with a particular emphasis on the Local Self Consistent Field method developed in our group. 

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