International Journal of Quantum Chemistry

Cover image for Vol. 113 Issue 9

5 May 2013

Volume 113, Issue 9

Pages i–iv, 1245–1425

  1. Cover Image

    1. Top of page
    2. Cover Image
    3. Full Papers
    4. Letters to the Editor
    1. You have free access to this content
      Cover Image, Volume 113, Issue 9 (pages i–ii)

      Article first published online: 20 MAR 2013 | DOI: 10.1002/qua.24439

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      The article by Ciann-Dong Yang and Kuan-Chang Su on page 1253 deals with a renewed interpretation of slit experiments from the viewpoint of complex quantum trajectories. Millions of complex quantum trajectories emerging from the slits can be solved from the quantum Hamilton equations of motion and their arrivals on a screen are recorded. The statistical distribution of the computed arrivals is analyzed in light of wavefunction statistics, in the form of probability density function Ψ*Ψ. The study shows for the first time that when enough quantum trajectories are involved in the computation of statistics, Ψ*Ψ in slit experiments can be predicted by the study of the arrivals of the quantum trajectories on the screen.

    2. You have free access to this content
      Inside Cover, Volume 113, Issue 9 (pages iii–iv)

      Article first published online: 20 MAR 2013 | DOI: 10.1002/qua.24440

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      The role of metal ions is central to the stabilization of the structure and the working of proteins, nucleic acids, and peptide hormones. In particular metal ions are known to aid intramolecular proton transfer processes in biological systems, as discussed in the case of 2-(3'-hydroxy-2'- pyridyl)benzoxazole in the article on page 1316 by Pinggui Yi, Zhengjun Liu, Zhaoxu Wang, Xianyong Yu, Jiming Zhou, Bo Hou, and Qingzhong Li.

  2. Full Papers

    1. Top of page
    2. Cover Image
    3. Full Papers
    4. Letters to the Editor
    1. Computational study of tautomerism and aromaticity in mono- and dithio-substituted tropolone (pages 1245–1252)

      S. W. Paine and A. Salam

      Article first published online: 10 JUL 2012 | DOI: 10.1002/qua.24268

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      Thiotropolone is characterized, both in molten and solid phase, by a quick intramolecular proton transfer between its two tautomeric forms. High-level electronic structure computations provide insight on the keto-enol tautomeric equilibrium constants and the extent of aromaticity in these species. It was found that enol forms predominate over keto structures by several orders of magnitude in both phases.

    2. Reconstructing interference fringes in slit experiments by complex quantum trajectories (pages 1253–1263)

      Ciann-Dong Yang and Kuan-Chang Su

      Article first published online: 10 JUL 2012 | DOI: 10.1002/qua.24269

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      Instead of conventional probability interpretation of two-slit experiments, it is quantitatively demonstrated that the experimentally observed interference fringes can be reconstructed by quantum trajectories. Tens of millions of complex quantum trajectories are computed to show that the distribution of their arrivals on the screen has a high degree of resemblance with the Fraunhofer diffraction pattern through a square aperture.

    3. Theoretical prediction for the structures of gas phase lithium oxide clusters: (Li2O)n (n = 1–8) (pages 1264–1271)

      Yuan Yuan and Longjiu Cheng

      Article first published online: 12 JUL 2012 | DOI: 10.1002/qua.24274

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      Despite being among the simplest metal-oxide clusters, the determination of the stable structures of small (Li2O)n clusters is very challenging from a theoretical viewpoint. Unbiased global minima search combining genetic algorithms with density functional theory reveals that for n over 3, a tetrahedral unit is found in most of the stable structures. In such a unit, the Li center has a very low charge and is bonded to four O atoms by sp3 interactions.

    4. A comparison of the effect of nanotube chirality and electronic properties on the π–π interaction of single-wall carbon nanotubes with pyrazinamide antitubercular drug (pages 1272–1284)

      Nabanita Saikia and Ramesh C. Deka

      Article first published online: 16 JUL 2012 | DOI: 10.1002/qua.24275

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      Drug delivery aided by carbon nanotubes is a very promising research area. Density functional theory calculations shine a light on the nature of the interaction between the anti-tubercular pyrazinamide drug and single-wall nanotubes. Insight into the modulation of nanotube electronic properties upon functionalization with pyrazinamide are of paramount importance to avoid adverse side-effects and high-toxicity of this drug delivery system.

    5. Theoretical studies of the band structure and optoelectronic properties of ZnOxS1−x (pages 1285–1292)

      Imad Khan and Iftikhar Ahmad

      Article first published online: 16 JUL 2012 | DOI: 10.1002/qua.24277

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      ZnO and ZnS are direct bandgap semiconductors, and their wide gap provides high breakdown voltages and emission in the blue/near UV region of the spectrum. The optoelectronic properties of their ternary alloys, ZnO xS1−x, are simulated to verify possible applications of this material in photonic devices operating in visible to UV spectral regions. As it is found to have similar character to III[BOND]N[BOND]V, ZnO xS1−x has potential to replace these materials in optoelectronic technology.

    6. Is a MH (M = Be and Mg) radical a better electron donor in halogen-hydride interaction?: A theoretical comparison with HMH (pages 1293–1298)

      Xiangbin Bai, Qingzhong Li, Ran Li, Jianbo Cheng and Wenzuo Li

      Article first published online: 12 JUL 2012 | DOI: 10.1002/qua.24279

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      Traditionally, halogen bonding has been thought of as an electrostatically driven interaction. However, an unexpected mechanism of this kind of bonding cannot be rationalized with this picture. This work studies the relative electron donating nature of the M[BOND]H bond and the H[BOND]M[BOND]H bond (M = Be and Mg) and finds that MH is a better electron donor in the halogen-hydride interaction than HMH. The enhancement of halogen-hydride interaction is dependent on the nature of halogen atom and metal hydride.

    7. A density functional theory investigation on the formation mechanisms of DNA interstrand crosslinks induced by chloroethylnitrosoureas (pages 1299–1306)

      Li-Jiao Zhao, Xin-Yan Ma and Ru-Gang Zhong

      Article first published online: 16 JUL 2012 | DOI: 10.1002/qua.24283

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      Chloroethylnitrosoureas (CENUs) are important agents used in the clinical treatment of cancer. The anticancer mechanism of CENUs involves the formation of DNA interstrand crosslinks, which mainly occur between guanine and cytosine, and are induced by the chloroethyl-diozonium ion obtained from decomposition of CENUs. This mechanism for the formation of G–C crosslink is clarified here by means of density functional theory calculations.

    8. Recursion relations for the three-electron subsidiary integral W (l, m, n; α, β, γ) (pages 1307–1315)

      Chun Li, Liming Wang and Zong-Chao Yan

      Article first published online: 17 JUL 2012 | DOI: 10.1002/qua.24284

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      The subsidiary integral W(l, m, n; α, β, γ) is a key integral that appears in the variational calculation of a three-electron atomic system using Hylleraas coordinates. For the case where the ratio α/(α + β + γ) is not close to 1, the W integral can be calculated by an infinite series which converges very fast. For the case where the ratio α/(α + β + γ) is close to 1, it can be expressed in terms of either a finite series or a finite recursion relation.

    9. Effect of metal cations [Li+, Na+, K+, Be2+, Mg2+, and Ca2+] on the structure of 2-(3′-hydroxy-2′-pyridyl)benzoxazole: A theoretical investigation (pages 1316–1324)

      Pinggui Yi, Zhengjun Liu, Zhaoxu Wang, Xianyong Yu, Jiming Zhou, Bo Hou and Qingzhong Li

      Article first published online: 20 JUL 2012 | DOI: 10.1002/qua.24286

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      To understand the role of metal cations in the structures of 2-(3′-hydroxy-2′-pyridyl)benzoxazole at the atomic and electronic levels, different ions, for example, Li+, Na+, K+, Be2+, Mg2+, Ca2+ have been investigated in the present article. The multiplicity of the binding between the M n+ and HPyBO, the most stable geometries of the metal complexes, and their binding strength and nature, are obtained using density functional theory.

    10. Structuring and destructuring effects along a pathway toward formation of zwitterionic glycine···(H2O)2 complex: many body analysis of clusters and molecular electrostatic potential investigations (pages 1325–1332)

      Anant D. Kulkarni, Dhurba Rai, Shridhar P. Gejji, Libero J. Bartolotti and Rajeev K. Pathak

      Article first published online: 20 JUL 2012 | DOI: 10.1002/qua.24287

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      This work demonstrates, at the molecular level, the process of zwitterion formation of glycine, induced by two approaching water molecules. The change from normal to zwitterionic configuration is traced through a local molecular electrostatic potential environment. Further, a many-body interaction analysis is performed to probe molecular cooperativity.

    11. Electronuclear multiconfiguration time-dependent hartree calculations on the confined H atom with mobile electron and nucleus (pages 1333–1338)

      Dimitrios Skouteris and Antonio Laganà

      Article first published online: 24 JUL 2012 | DOI: 10.1002/qua.24295

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      The energy levels of the free hydrogen atom can be calculated analytically from the Schrödinger equation. But how do these levels change if the H atom is confined in a spherical cavity? Here a multi-configuration time-dependent Hartree algorithm is used to treat this six-dimensional problem and obtain a picture of the confined H atom energy levels. At high energies, the energy levels diverge and thus a calculation of the partition function of the H atom becomes tractable.

    12. The role of benzoic acid in proline-catalyzed asymmetric michael addition: A density functional theory study (pages 1339–1348)

      Hongwei Shi, Xiangui Huang, Guixia Liu, Kunqian Yu, Congying Xu, Weihua Li, Bubing Zeng and Yun Tang

      Article first published online: 20 JUL 2012 | DOI: 10.1002/qua.24297

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      Asymmetric Michael addition reactions, catalyzed by proline, yield only a trace amount of the desired product. The addition of benzoic acid and its derivatives improves the results. Density functional theory calculations explain the important roles of benzoic acid and the differences in yield obtained using different derivatives.

    13. Electronic, spectra, and spin orbit interaction for FrAr van der Waals system (pages 1349–1357)

      Hamid Berriche

      Article first published online: 23 AUG 2012 | DOI: 10.1002/qua.24302

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      Alkali metal-rare gas systems serve as models for investigating collisional process such as line broadening, quenching, and electronic energy transfer. This work presents a theoretical investigation of the potential curves and absorption spectra for the ground and excited states of FrAr, based on a pseudopotentials approach that efficiently reduces the complexity of the calculation to a one-electron problem.

    14. Novel theoretical studies of the dehydrogenation of LiBH2NH3 (pages 1358–1364)

      Kun Wang, Jian-Guo Zhang, Tian-Tian Man, Man Wu, Shao-Wen Zhang, Tong-Lai Zhang and Li Yang

      Article first published online: 3 AUG 2012 | DOI: 10.1002/qua.24304

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      For the first time an alternative dehydrogenation mechanism is reported for a alkali-metal aminoborane. Calculations lead to the determination of all the species involved in the reaction and their characterization using vibrational spectroscopy. The rate constants for these reactions are also determined theoretically. These results may open a new route for the development of new hydrogen storage materials.

    15. Computational studies of the corrosion-inhibition efficiency of iron by triazole surfactants (pages 1365–1371)

      M'hamed Touil, Najat Hajjaji, Dage Sundholm and Hassan Rabaâ

      Article first published online: 6 AUG 2012 | DOI: 10.1002/qua.24310

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      The inhibition by certain organic surfactants of the corrosion processes on iron surfaces is believed to be caused by the formation of donor-acceptor complexes between the surface and the organic inhibitors. Perturbation theory is applied here to the investigation of the structural relationships between the corrosion-inhibition efficiency and the molecular properties of the surfactant molecules, specifically in the case of steel corrosion in an acidic medium.

    16. Unified analytical treatment for calculation of the two-dimensional Franck–Condon factors using the duschinsky transformation (pages 1372–1375)

      B. A. Mamedov

      Article first published online: 13 AUG 2012 | DOI: 10.1002/qua.24313

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      The Franck–Condon overlap integrals between the two electronic states determine the transition probabilities for various vibrational levels as well as intensities of various lines in the spectra of diatomic and polyatomic molecules. Using the Duschinsky effect, an efficient analytical calculation approach to compute the two-dimensional Franck-Condon factors, as the squares of the overlap intergrals are also known, is introduced in this work.

    17. Theoretical study of novel porphyrins bearing electron donor–acceptor groups (pages 1376–1383)

      Carolina Caicedo, Ana Martínez and Ernesto Rivera

      Article first published online: 13 AUG 2012 | DOI: 10.1002/qua.24316

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      The electronic structure and the donor-acceptor properties of some porphyrins are modeled by means of time-dependent density functional theory calculation to evaluate their possible use in solar cell technology. The electron donor-acceptor capacity of porphyrins is here characterized using two parameters; electrodonating and electroaccepting electronegativity.

    18. DFT study of the physicochemical characteristics and spectral behavior of new 8-substituted 1,3,7-trimethylxanthines (pages 1384–1393)

      Stancho Stanchev, Javor Mitkov, Maya Georgieva and Alexander Zlatkov

      Article first published online: 28 AUG 2012 | DOI: 10.1002/qua.24320

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      Purine alkaloids, such as caffeine, theophylline, theobromine, and methyluric acid, are known central nervous system stimulants. Nine newly synthesized trimethylxanthines of this class are compared in this study, and their characteristic spectral fingerprints are identified using density functional theory.

    19. Structure and cooperativity of the hydrogen bonds in sodium dihydrogen triacetate (pages 1394–1400)

      Ashour A. Ahmed, Oliver Kühn, Rifaat H. Hilal and Mohamed F. Shibl

      Article first published online: 25 SEP 2012 | DOI: 10.1002/qua.24328

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      Carboxylic acids are often used as models for aspartic and glutamic acid side chains, as they can mimic the complex hydrogen-bond networks of their larger biological counterparts. Two of such hydrogen bonded complexes, sodium dihydrogen triacetate and its anion, are studied here using density functional theory and, for both systems, two conformers of comparable energy are found. The proton transfer process and hydrogen-bond cooperativity in these system is evaluated by means of Born–Oppenheimer molecular dynamics.

    20. An orbital localization criterion based on the topological analysis of the electron localization function (pages 1401–1408)

      Ofelia B. Oña, Diego R. Alcoba, William Tiznado, Alicia Torre and Luis Lain

      Article first published online: 25 SEP 2012 | DOI: 10.1002/qua.24332

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      A new, computationally inexpensive, molecular orbital localization procedure, based on the spatial domains provided by the topological analysis of the electron localization function, is introduced here. This method overcomes few drawbacks of established treatments and preserves the separability of the σ/π bonds in planar molecules.

    21. Quantum chemistry studies of adenosine 2503 methylation by S-adenosylmethionine-dependent enzymes (pages 1409–1415)

      Chunling Wang, Xiaoke Yang, Endong Wang and Baiqing Li

      Article first published online: 25 SEP 2012 | DOI: 10.1002/qua.24333

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      A new reaction mechanism, which does not involve direct transfer of a methyl group from a radical S-adenosylmethionine enzyme to adenosine, is proposed for a pair of methyltransferase reactions. The activation barriers, calculated using density functional theory, indicate that the proposed reaction mechanism is plausible and the formation of a disulfide bond is likely the rate-limiting step.

    22. Theoretical computation of low-lying electronic states of HCNS: A CASPT2 study (pages 1416–1421)

      Chui-Peng Kong, Zeng-Xia Zhao and Hong-Xing Zhang

      Article first published online: 18 OCT 2012 | DOI: 10.1002/qua.24334

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      HCNS and its isomers have been detected in the interstellar cloud and are formed by decomposition of larger molecules upon UV irradiation. The excited state geometries, excitation energies, and adsorption wavelengths for these molecules are predicted using high-level quantum chemical methods.

  3. Letters to the Editor

    1. Top of page
    2. Cover Image
    3. Full Papers
    4. Letters to the Editor
    1. Reply to the comment by Vignale et al (pages 1424–1425)

      Xiao-Yin Pan and Viraht Sahni

      Article first published online: 12 OCT 2012 | DOI: 10.1002/qua.24326