Results 271 to 280 of about 487,810 (325)

Identity for Kullback-Leibler divergence in density functional reactivity theory.

Journal of Chemical Physics, 2019
Density functional reactivity theory (DFRT) makes use of simple electron density functionals to appreciate chemical reactivity. The Kullback-Leibler divergence, also called information gain or relative Shannon entropy, as a key component of the DFRT ...
Shubin Liu
semanticscholar   +1 more source

Chemical Reactivity and Excited-State Density Functional Theory

The Journal of Physical Chemistry A, 1999
Softness and polarizability are calculated for different complexions of two-state ensembles of various helium isoelectronic systems (He, Li+, Be2+, B3+, C4+). It is shown for the first time for the systems studied that an increase in the excited-state contribution in a two-state ensemble makes the system softer and more polarizable, as expected from ...
P. K. Chattaraj, A. Poddar
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Loge Theory and Chemical Reactivity

1976
For a long time the analysis of relations between molecular electronic structure and chemical reactivity was based on the use of static indices (like atomic charges, bond orders, free valence numbers). A large number of interesting results have been obtained by following that way [1].
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A reactive-flux theory of chemical surface diffusion

The Journal of Chemical Physics, 1990
A theory for calculating the surface chemical diffusion coefficient of adsorbates strongly bound to localized adsorption sites on a crystal surface is presented. The coefficient is expressed as the product of a transition state theory value that may be calculated by Monte Carlo methods and a dynamical correction factor that may be calculated by ...
Paul A. Rejto, Hans C. Andersen
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Chemical reactivity in the framework of pair density functional theories

Journal of Computational Chemistry, 2012
AbstractChemical reactivity descriptors are derived within the framework of the pair density functional theory. These indices provide valuable information about bonding rearrangements and activating mechanisms upon electrophilic or nucleophilic reactions.
Nicolás, Otero, Marcos, Mandado
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One-Determinental Theory of Chemical Reactivity

1978
Qualitative organic theory involves the reduction of quantum mechanical equations to simple concepts. We examine the sequential steps needed to make a transition from the ab initio Self Consistent Field MO (SCF MO) method to the qualitative One Electron MO (OEMO) model which currently constitutes the theoretical framework for most discussions of ...
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Perspectives on the Role of the Frontier Effective-for-Reaction Molecular Orbital (FERMO) in the Study of Chemical Reactivity: An Updated Review

, 2020
Molecular orbitals are critical in the rationalization of several chemical reactions. Thus, the frontier molecular orbital theory, proposed by Fukui's group, postulated the importance of the Highest Occupied Molecular Orbital (HOMO) and the Lowest ...
L. Braga, Daniel H. S. Leal, K. Kuča, T. Ramalho   +3 more
semanticscholar   +1 more source

Chemical reactivity indexes in density functional theory

Journal of Computational Chemistry, 1999
The theoretical description of charge distribution, and related properties, such as chemical reactivity descriptors of chemical compounds, has greatly benefited from the development of density functional theory (DFT) methods. Indeed, most concepts stemmed from DFT but, up to now, they have been used mostly within semiempirical MO methods, Hartree–Fock,
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Chemical Reactivity from Molecular Orbital Theory. Electrophilic Aromatic Substitutions

Journal of the Chinese Chemical Society, 1967
AbstractA new method of correlating experimental reactivities with parameters calculated by molecular orbital theory, is proposed. In the case of electrophilic aromatic substitutions, this new approach shows significant improvement over the previous attempts.
D.P. Chong, C. Mundhenk
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Average electronic energy is the central quantity in conceptual chemical reactivity theory

Theoretical Chemistry accounts, 2016
Marco Franco-Pérez, P. Ayers, J. Gázquez   +2 more
semanticscholar   +1 more source