Results 281 to 290 of about 134,957 (331)
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Gradients in valence bond theory
The Journal of Chemical Physics, 1999A gradient method for general valence bond wave functions is presented. The electronic energy is used as a Lagrange multiplier. The derivatives of the normalization and of the first- and second-order cofactors present in the energy expression have to be evaluated, giving rise to first-, second-, and third-order cofactors.
Dijkstra, Fokke, Van Lenthe, Joop H.
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1992
It was once claimed (Pauling and Wilson, 1935), and is still widely accepted, that the classic paper by Heitler and London (1927) “must be considered the greatest single contribution to the chemist’s conception of valence that has been made since G. N.
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It was once claimed (Pauling and Wilson, 1935), and is still widely accepted, that the classic paper by Heitler and London (1927) “must be considered the greatest single contribution to the chemist’s conception of valence that has been made since G. N.
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Spin-coupled valence bond theory
International Reviews in Physical Chemistry, 1988Abstract In the spin-coupled description of molecular electronic structure, an N-electron system is described by N distinct—but non-orthogonal—orbitals, whose spins are coupled to the required resultant S in all possible ways. The coefficients of the basis functions comprising the orbitals and the coefficients of the different spin functions are fully ...
D. L. Cooper, J. Gerratt, M. Raimondi
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1977
In this chapter, we build on the ideas developed in our treatment of H2 (Sections 8.3–8.5). We will not be able to do much in the way of complete calculations, for which there should be no regrets. Rather, we try to generalize the results for H2 to other systems in a semi-intuitive way.
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In this chapter, we build on the ideas developed in our treatment of H2 (Sections 8.3–8.5). We will not be able to do much in the way of complete calculations, for which there should be no regrets. Rather, we try to generalize the results for H2 to other systems in a semi-intuitive way.
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ChemInform Abstract: Modern Valence Bond Theory
ChemInform, 1997AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
J. GERRATT +3 more
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Valence bond theory of aromaticity
Journal of the American Chemical Society, 1984Etude de l'aromaticite par la methode de la liaison de valence en tenant compte de la permutation des cycles, ce qui permet de rendre compte du courant de cycle et de l'antiaromaticite.
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The Pair Bond Theory of Valency
Nature, 1935THE method of molecular orbitals (Hund, Mulliken, Lennard-Jones), which is especially designed for the description of a completed molecule can be worked out in high approximations only in the simplest cases. In more complicated ones, it is therefore not able to describe the process of dissociation, which is clearly the essential requirement of a theory
H. LESSHEIM, R. SAMUEL
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Valence-bond theory and chemical structure
Journal of Chemical Education, 1990History of the development of VB theory, solid-state applications of VB theory, semiempirical VB models, VB theory in textbooks, and criticism of VB theory.
Douglas J. Klein, Nenad Trinajstic
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The valence bond theory of molecular structure - I. Orbital theories and the valence-bond method
Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences, 1954The molecular orbital (MO) and valence bond (VB) theories of the electronic structure of molecules emerge from one quite general approximation method involving the use of anti-symmetrized products (AP’s) of one-electron wave function (‘orbitals’), differing fundamentally only in their choice of a first approximation; in MO theory this is ...
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Advances in valence bond theory
2008Since the early days of quantum mechanics, there have been two distinct approaches to the description of molecular electronic structure: Molecular orbital (MO) theory and the valence bond (VB) method.
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