A Continuous Symmetry Analysis of Chemical Bonding

Authors

  • Dr. Chaim Dryzun,

    1. Institute of Chemistry and The Lise Meitner Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904 (Israel)
    2. Current address: Department of Chemistry and Applied Biosciences, Computational Science, ETH Zürich, USI Campus, Via Giuseppe Buffi 13, Lugano CH-6900 (Switzerland)
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  • Dr. Pere Alemany,

    Corresponding author
    1. Departament de Química Física and Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, Martí i Franqués 1-11, 08028 Barcelona (Spain), Fax: (+34) 93-402-1231
    • Departament de Química Física and Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, Martí i Franqués 1-11, 08028 Barcelona (Spain), Fax: (+34) 93-402-1231
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  • Dr. David Casanova,

    1. Departament de Química Física and Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, Martí i Franqués 1-11, 08028 Barcelona (Spain), Fax: (+34) 93-402-1231
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  • Prof. David Avnir

    1. Institute of Chemistry and The Lise Meitner Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904 (Israel)
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Abstract

The ability to quantify the symmetry content of a given molecular system is important both for the quantitative prediction of its physical and chemical properties, as well as for the establishment of powerful theoretical concepts that can be derived solely from symmetry considerations. The symmetry content of a complex object such as a molecule relies, however, on the level of structural description that is chosen. This may range form a simple geometrical picture in which only the position of the nuclei is indicated, to a more or less detailed description of the electronic structure given by the different quantum chemical methods. Recently, a paper was published describing a new general methodology for calculating the symmetry content of diverse mathematical objects, such as vectors, operators, matrices, functions and more. In the present work we apply that approach to explore the inversion symmetry for diatomic molecules. Although it is a very simple system, general physical conclusions on the phenomenon of chemical bonding can be easily obtained from the symmetry analysis at different levels of description.

Abstract

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Abstract

En aquest treball s’ha aplicat el llenguatge de les mesures contínues de simetria (CSM) per explorar els efectes que té un trencament de la simetria en un enllaç químic. Per a això s’ha calculat el contingut en simetria d’inversió per al hamiltonià, la densitat electrònica, les poblacions atòmiques i els orbitals moleculars de molècules diatòmiques, tant homonuclears, A2, com heteronuclears, AB. Aquest nou enfoc posa clarament de manifest l’existència de relacions quantitatives entre conceptes fonamentals en la teoria de l’enllaç químic, com ara la covalència o la ionicitat d’un enllaç, amb les fonts d’asimetria en la molècula.

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