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Zhou X.-Y.,Changde Vocational Technical College | Rong C.,Hunan Normal University | Lu T.,Beijing Kein Research Center for Natural science | Zhou P.,Lanzhou University | Liu S.,University of North Carolina at Chapel Hill
Journal of Physical Chemistry A | Year: 2016

How to accurately predict electronic properties of a Columbic system with the electron density obtained from experiments such as X-ray crystallography is still an unresolved problem. The information-theoretic approach recently developed in the framework of density functional reactivity theory is one of the efforts to address the issue. In this work, using 27 atoms and 41 molecules as illustrative examples, we present a study to demonstrate that one is able to satisfactorily describe such electronic properties as the total energy and its components with information-theoretic quantities like Shannon entropy, Fisher information, Ghosh-Berkowitz-Parr entropy, and Onicescu information energy. Closely related to the earlier attempt of expanding density functionals using simple homogeneous functionals, this work not only confirms Nagy's proof that Shannon entropy alone should contain all the information needed to adequately describe an electronic system but also provides a feasible pathway to map the relationship between the experimentally available electron density and various electronic properties for Columbic systems such as atoms and molecules. Extensions to other electronic properties are straightforward. © 2016 American Chemical Society. Source

Manzetti S.,Performance Technology | Manzetti S.,Uppsala University | Lu T.,Beijing Kein Research Center for Natural science | Behzadi H.,Kharazmi University | And 3 more authors.
RSC Advances | Year: 2015

Solar cell technologies are highly dependent on silicon materials and novel nanoclusters with optimal electronic properties. Based on a recent study on ultrastable silicon nanoclusters, an analysis of the effects of modifications of those nanocrystals by carboxylation, amidation, hydroxylation and halogenation has been performed using quantum mechanical methods of study. Here we report the gaps, electronic structures, absorption spectra, and effects on the charge-transfer potential of a collection of modified silicon nanoclusters. The results show that the pristine silicon clusters retain the highest charge-transfer properties and that halogenation impacts on the charge-transfer effects in a proportional fashion to the electronegativity of the employed halogens. Modification with organic molecules does not improve charge-transfer properties, and gives instead the highest reduction of charge-transfer potentials of the silicon clusters. The effects of the modification have also been studied in context with the orbital configurations through wave function analysis, which reveals that the electrostatic properties of the nanoclusters are mainly represented by a significant polarization of the electrostatic energy between the peripheral regions of the clusters and their core, a feature particularly well-preserved in the pristine silicon clusters. Modifying the particles by adding an extra atom at their core shows significant effects on the molecular orbital properties (HOMO/LUMO). However, this modification does not contribute to an actual increase in charge-transfer integrals. The modifications induce, however, interesting effects on the overall configuration of the clusters; i.e., they increase the aromatic character of the inter-atomic bonding pattern. Halogenation has the highest effect on improving aromatic properties for the silicon clusters, where chlorination gives the highest degree of aromaticity. This study introduces valuable electronic data for engineering novel silicon nanoclusters for application in solar cell technologies, computing units, and other fields such as in aerospace engineering. © The Royal Society of Chemistry 2015. Source

Liu S.-B.,Hunan Normal University | Liu S.-B.,University of North Carolina at Chapel Hill | Rong C.-Y.,Hunan Normal University | Wu Z.-M.,Hunan Normal University | Lu T.,Beijing Kein Research Center for Natural science
Wuli Huaxue Xuebao/ Acta Physico - Chimica Sinica | Year: 2015

Density functional theory dictates that the electron density determines everything in a molecular system’s ground state, including its structure and reactivity properties. However, little is known about how to use density functionals to predict molecular reactivity. Density functional reactivity theory is an effort to fill this gap: it is a theoretical and conceptual framework through which electron-related functionals can be used to accurately predict structure and reactivity. Such density functionals include quantities from the information-theoretic approach, such as Shannon entropy and Fisher information, which have shown great potential as reactivity descriptors. In this work, we introduce three closely related quantities: Rényi entropy, Tsallis entropy, and Onicescu information energy. We evaluated these quantities for a number of neutral atoms and molecules, revealing their scaling properties with respect to electronic energy and the total number of electrons. In addition, using the example of second-order Onicescu information energy, we examined how its patterns change with the angle of dihedral rotation of an ethane molecule at both the molecular level and atoms-in-molecules level. Using these quantities as additional reactivity descriptors, researchers can more accurately predict the structure and reactivity of molecular systems. © Editorial office of Acta Physico-Chimica Sinica. Source

Wu W.,Hunan University | Wu Z.,Hunan Normal University | Rong C.,Hunan Normal University | Rong C.,McMaster University | And 4 more authors.
Journal of Physical Chemistry A | Year: 2015

The electrophilic aromatic substitution for nitration, halogenation, sulfonation, and acylation is a vastly important category of chemical transformation. Its reactivity and regioselectivity is predominantly determined by nucleophilicity of carbon atoms on the aromatic ring, which in return is immensely influenced by the group that is attached to the aromatic ring a priori. In this work, taking advantage of recent developments in quantifying nucleophilicity (electrophilicity) with descriptors from the information-theoretic approach in density functional reactivity theory, we examine the reactivity properties of this reaction system from three perspectives. These include scaling patterns of information-theoretic quantities such as Shannon entropy, Fisher information, Ghosh-Berkowitz-Parr entropy and information gain at both molecular and atomic levels, quantitative predictions of the barrier height with both Hirshfeld charge and information gain, and energetic decomposition analyses of the barrier height for the reactions. To that end, we focused in this work on the identity reaction of the monosubstituted-benzene molecule reacting with hydrogen fluoride using boron trifluoride as the catalyst in the gas phase. We also considered 19 substituting groups, 9 of which are ortho/para directing and the other 9 meta directing, besides the case of R = -H. Similar scaling patterns for these information-theoretic quantities found for stable species elsewhere were disclosed for these reactions systems. We also unveiled novel scaling patterns for information gain at the atomic level. The barrier height of the reactions can reliably be predicted by using both the Hirshfeld charge and information gain at the regioselective carbon atom. The energy decomposition analysis ensued yields an unambiguous picture about the origin of the barrier height, where we showed that it is the electrostatic interaction that plays the dominant role, while the roles played by exchange-correlation and steric effects are minor but indispensable. Results obtained in this work should shed new light for better understanding of the factors governing the reactivity for this class of reactions and assisting ongoing efforts for the design of new and more efficient catalysts for such kind of transformations. (Graph Presented). © 2015 American Chemical Society. Source

Cao J.,University of Science and Technology of China | Ren Q.,University of Science and Technology of China | Chen F.,University of Science and Technology of China | Lu T.,Beijing Kein Research Center for Natural science
Science China Chemistry | Year: 2015

Predicting the reactivity of nucleophilic reaction at different sites has important theoretical and practical significance. Many prediction methods solely based on the electronic structure of reactants have been proposed. In this paper, detailed comparative analyses on the reliability of 14 methods are carried out and three series of molecules, carbonyl compounds, aromatic hydrocarbons and pyridine derivatives are exploited as test systems. It is found that the methods reflecting local electronic softness, such as condensed dual descriptor, have satisfactory prediction ability; while the ones reflecting electrostatic effect, such as atomic charge analysis and electrostatic potential analysis, have evidently worse overall performance. For all systems of interest, condensed dual descriptor and Hirshfeld charge display the most robust predictive capacity. © 2015 Science China Press and Springer-Verlag Berlin Heidelberg. Source

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