International Journal of Quantum Chemistry

Cover image for Vol. 113 Issue 11

5 June 2013

Volume 113, Issue 11

Pages i–iv, 1603–1667

  1. Cover Image

    1. Top of page
    2. Cover Image
    3. Perspective
    4. Reviews
    5. Full Papers
    1. You have free access to this content
      Cover Image, Volume 113, Issue 11 (pages i–ii)

      Version of Record online: 18 APR 2013 | DOI: 10.1002/qua.24454

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      The theory of elementary catastrophes has inspired a new non-Euclidean quantum mechanics-based geometry to describe the topology of molecules and clusters. The Perspective article by Samantha Jenkins on page 1603 discusses the current research that explores the relationship between the topology of the molecules and the phase space for both the molecular and the solid-state topologies, as well as an alternative application of the Poincaré-Hopf relation. The four different types of quantum geometry dimension are shown in the cover image along with the corresponding form of the Poincaré-Hopf relation depending on the types of critical point present.

    2. You have free access to this content
      Inside Cover, Volume 113, Issue 11 (pages iii–iv)

      Version of Record online: 18 APR 2013 | DOI: 10.1002/qua.24455

      Thumbnail image of graphical abstract

      The cover shows three of the components that go into the formation of a noncovalent pnicogen bond, in this case the FH2P...NH3 complex. The upper diagram represents charge transfer from the N lone pair into the vacant σ* P-F antibonding orbital. The Coulombic attraction between the electrostatic potentials of the FH2P and NH3 subunits is illustrated in the middle figure. The lower figure depicts the shifts of electron density that occur when the two molecules combine to form the pnicogen-bonded complex, with charge shifting from green areas to purple. In the Review on page 1609, Steve Scheiner gives an overview of this type of noncovalent interaction, drawing parallelisms with the related chalcogen, halogen, and H-bonds.

  2. Perspective

    1. Top of page
    2. Cover Image
    3. Perspective
    4. Reviews
    5. Full Papers
    1. You have free access to this content
      Quantum topology phase diagrams for molecules, clusters, and solids (pages 1603–1608)

      Samantha Jenkins

      Version of Record online: 1 FEB 2013 | DOI: 10.1002/qua.24398

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      The promising early beginnings of the theoretical development of the Poincaré–Hopf relation, abandoned in the early 1980s, have inspired the recent creation of quantum topology phase diagrams to predict new isomer topologies. Alternative uses of the Poincaré–Hopf and Euler–Poincaré relations, for example, for molecular recognition and phase transitions in solids, respectively, are discussed. A perspective is given and it is demonstrated that within the quantum topology framework, new theory can be created to link with traditional chemical ideas.

  3. Reviews

    1. Top of page
    2. Cover Image
    3. Perspective
    4. Reviews
    5. Full Papers
    1. You have free access to this content
      Detailed comparison of the pnicogen bond with chalcogen, halogen, and hydrogen bonds (pages 1609–1620)

      Steve Scheiner

      Version of Record online: 29 OCT 2012 | DOI: 10.1002/qua.24357

      Thumbnail image of graphical abstract

      Pnicogen bonds represent a very real type of noncovalent interaction, with parallels to chalcogen, halogen bonds, and H-bonds. All these noncovalent bonds are quite similar in strength and nature and owe their stability to a mixture in nearly equal parts of electrostatic attraction and charge transfer, along with a smaller dispersion component. Pnicogen bonds can be tuned, in the same way that hydrogen and halogen bonds are, for the rational design of large molecular systems.

  4. Full Papers

    1. Top of page
    2. Cover Image
    3. Perspective
    4. Reviews
    5. Full Papers
    1. A mechanism for the addition of ethylene to nickel bis-dithiolene (pages 1621–1625)

      Mohamed F. Shibl, Li Dang, Rajesh K. Raju, Michael B. Hall and Edward N. Brothers

      Version of Record online: 4 DEC 2012 | DOI: 10.1002/qua.24370

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      Olefin refinement is expensive in part due to the cost of the energy required to perform cryogenic distillation. One way to avoid this expensive step is via an electrochemical procedure based on nickel (bis)dithiolene's ability to reversibly bind ethylene. However, there remains many open questions on the mechanism of this reaction. This work proposes a new route to the initial binding of ethylene by the nickel complex.

    2. Exact relations between the electron density and external potential for systems of interacting and noninteracting electrons (pages 1626–1632)

      Ilya G. Ryabinkin and Viktor N. Staroverov

      Version of Record online: 21 DEC 2012 | DOI: 10.1002/qua.24374

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      The differential virial theorem—an exact explicit relation between the Kohn–Sham effective potential, electron density, and two orbital-dependent quantities—is revisited and derived in a new way. The significance of this relation is that it can be used to determine exchange-correlation potentials from given electron densities and to analyze the density-potential mapping. It may also play a role in the development of density-functional methods for excited states.

    3. Exploration of the reactivity of N2O5 with two Si(OH)4 monomers using electronic structure methods (pages 1633–1640)

      Sabri Messaoudi, Bechir Bejaoui, Fourat Akrout, Malika Bel Hassen and Cherif Sammari

      Version of Record online: 22 DEC 2012 | DOI: 10.1002/qua.24378

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      The heterogeneous uptake of N2O5 on mineral dust particles may play an important role in the removal of nitrogen oxides from the atmosphere. However, the reaction of N2O5 with the mineral particles is not well understood. This study represents a first step towards understanding the interaction of N2O5 with the hydroxyl groups of silica particles.

    4. Efficient blue-emitting Ir(III) complexes with phenyl-methyl-benzimidazolyl and picolinate ligands: A DFT and time-dependent DFT study (pages 1641–1649)

      Ming-Xing Song, Zhao-Min Hao, Zhi-Jian Wu, Shu-Yan Song, Liang Zhou, Rui-Ping Deng and Hong-Jie Zhang

      Version of Record online: 8 JAN 2013 | DOI: 10.1002/qua.24379

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      Luminescent transition metal complexes are central to the high efficiencies obtained in phosphorescent organic light-emitting diodes (OLEDs). The development of high-efficiency red and green phosphors has revolutionized the display industry. However, the search for a high-efficiency pure-blue material has proven to be elusive. In this article, a series of Ir-based complexes are studied using time-dependent density functional theory. These complexes show desirable emission and charge injection characteristics, rendering them suitable for OLED displays.

    5. Density functional study of platinum polyyne monomer, oligomer, and polymer: Ground state geometrical and electronic structures (pages 1650–1659)

      Shahram Motaghiani and Kavoos Mirabbaszadeh

      Version of Record online: 3 JAN 2013 | DOI: 10.1002/qua.24380

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      Rigid rod metallopolyynes are the promising candidates for use in organic solar cells. In this work, platinum polyyne oligomers have been studied using density functional theory. The results confirm that low-energy vertical transitions have charge transfer character. Improved exciton transport and higher stability due to the presence of Pt makes such molecules good candidates for photovoltaic applications.

    6. Locating apoptosis proteins by incorporating the signal peptide cleavage sites into the general form of Chou's Pseudo amino acid composition (pages 1660–1667)

      Yufang Qin, Li Zheng and Jifeng Huang

      Version of Record online: 3 JAN 2013 | DOI: 10.1002/qua.24383

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      The prediction of subcellular location for apoptosis proteins has attracted great attention due to the essential role in understanding the mechanism of programmed cell death and their biological functions. Although improved prediction accuracies are now possible, some realistic biological information has been neglected. In this work, a new apoptosis protein localization scheme is proposed based on the predicted cleavage sites of primary protein sequences and stereochemical classification of amino acids.

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