International Journal of Quantum Chemistry

Cover image for Vol. 114 Issue 21

Early View (Online Version of Record published before inclusion in an issue)

Online ISSN: 1097-461X

Associated Title(s): Journal of Computational Chemistry

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  1. Full Papers

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      Time-dependent molecular fields created by the interaction of an external electromagnetic field with a molecular system

      Michael Baer

      Article first published online: 15 JUL 2014 | DOI: 10.1002/qua.24734

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      The interaction between the Born Oppenheimer non-adiabatic coupling terms (NACT) and an external electromagnetic field, at the vicinity of a conical intersection, is treated. It is shown that such an interaction results in a Wave Equation, for each component of the NACTs:

      In these equations c is the velocity of light, inline image is the time-dependent potential exerted by the dipole interaction with an external field and p and q are any two Cartesian coordinates (the extension to a larger number of coordinates is straightforward).

    2. Investigation of dephasing in an open quantum system under chaotic influence via a fractional Kohn–Sham scheme

      Timothy Ganesan

      Article first published online: 12 JUL 2014 | DOI: 10.1002/qua.24735

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      The dephasing of interacting many-electron systems under chaotic influence is an unexplored complex phenomenon. An effort toward a more complete theoretical understanding of its dynamics is performed using fractional formulations. Using this approach, some interesting insights are uncovered and these findings are examined in detail.

    3. A DFT study of reactions of methyldiazonium ion with DNA/RNA nucleosides: Investigating effect of sugar moiety on methylation pattern of bases

      Kanika Bhattacharjee and Pradeep Kumar Shukla

      Article first published online: 8 JUL 2014 | DOI: 10.1002/qua.24733

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      The alkylation reaction of DNA and RNA is of particular interest as it has been linked to mutation and cancer. Alkylation patterns depend on the alkylating agents, the position in DNA/RNA and on whether DNA is single- or double-stranded. Density functional theory calculations show how the methylation pattern of bases in DNA nucleosides differs from those in RNA nucleosides when they are exposed to methyldiazonium ion

    4. Scale-adaptive tensor algebra for local many-body methods of electronic structure theory

      Dmitry I. Lyakh

      Article first published online: 7 JUL 2014 | DOI: 10.1002/qua.24732

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      A formalism called scale-adaptive tensor algebra (SATA) introduces an adaptive representation of tensors of many-body operators via the local adjustment of the basis set quality. SATA is expected to enhance the applicability of certain local correlated many-body methods of electronic structure theory, as the use of smaller basis for weak off-diagonal blocks reduces the computational costs of the calculations.

    5. Arbitrary l-wave bound states of the Schrödinger equation for the hyperbolical molecular potential

      Gao-Feng Wei and Wen-Li Chen

      Article first published online: 3 JUL 2014 | DOI: 10.1002/qua.24731

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      The hyperbolical potential, as one of the important molecular model potential, has been widely used to describe the vibrational spectra of the ammonia molecule. An algebraic method is applied to the study of the parameter dependence of arbitrary wave bound in the non-relativistic theory, and it is then employed to derive the analytical energy levels of the Schrödinger equation with the hyperbolical potential.

    6. Theoretical study on SH2 reaction of methyl radical with three-membered ring

      Xiang Zhang

      Article first published online: 3 JUL 2014 | DOI: 10.1002/qua.24730

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      Bimolecular homolytic substitution (SH2) reactions are regarded as one of the principle tools in synthetic chemistry. SH2 reactions of methyl radical with three-membered ring compounds proceed dominantly via backside displacement. Theoretical analysis reveals that the methyl radical acts predominantly as a nucleophilic radical. These reactions can be divided into three groups and each group exhibits good correlation between distortion and overall activation enthalpies, in a way that can be well explained by Marcus theory.

    7. Study of simulation method of time evolution of atomic and molecular systems by quantum electrodynamics

      Kazuhide Ichikawa, Masahiro Fukuda and Akitomo Tachibana

      Article first published online: 28 JUN 2014 | DOI: 10.1002/qua.24726

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      When an electron moves, it creates an electromagnetic field around itself, and in turns this field has an effect on the electron. In quantum electrodynamics (QED), in which electromagnetic field is quantized to be photons, this so-called self-energy effect is viewed as the process in which the electron emits a photon and then absorbs it back. How to describe the self-energy effect in time-resolved QED simulations is the subject of this research.

    8. Simplified box orbitals: A Spatially Restricted Alternative to the Slater-Type Orbitals

      Victor García, David Zorrilla and Manuel Fernández

      Article first published online: 28 JUN 2014 | DOI: 10.1002/qua.24727

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      A new type of spatially restricted basis functions is introduced. The new functions are easy to use, but the test accomplished with atomic and molecular calculations lead to results similar to those found by using standard Slater-type-orbital basis functions. In order to facilitate the use of the new functions with standard quantum chemical packages, gaussian developments “-nG” for new functions are supplied.

    9. Catalytic Activities of Au6, Au 6−, and Au 6+ Clusters for CO oxidation: A density functional study

      Subhi Baishya and Ramesh C. Deka

      Article first published online: 18 JUN 2014 | DOI: 10.1002/qua.24725

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      Small gold clusters exhibit excellent catalytic activity toward many important reactions. Gold hexamer is one such small cluster with the potential to act as a catalyst for reactions like CO oxidation. Density Functional Theory shows that neutral, anionic, and cationic Au6 clusters exhibit different activity toward CO oxidation. Anionic Au6 is the catalytically most active cluster and the proposed pathway for CO oxidation on inline image requires no thermal activation.

  2. Tutorial Reviews

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      Basics of the spin Hamiltonian formalism

      Mohammad Mostafanejad

      Article first published online: 18 JUN 2014 | DOI: 10.1002/qua.24721

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      Based on the relation between quantum mechanical concepts such as effective Hamiltonians, perturbation theory and unitary transformations, and phenomenological aspects of the spin Hamiltonians, this tutorial tries to address the basics of the spin Hamiltonian formalism.

  3. Full Papers

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      A DFT investigation of the interactions of Pd, Ag, Sn, and Cs with silicon carbide

      Jeremy Rabone and Attila Kovács

      Article first published online: 18 JUN 2014 | DOI: 10.1002/qua.24720

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      The diffusion of radionuclides through the silicon carbide layers in tristructural isotropic coated fuel particles is an intriguing problem in nuclear industry. Density functional theory calculations on molecular and solid-state models provide insight into the nature of the interaction of palladium, silver, tin, and caesium with silicon carbide.

    2. ELF and its relatives—A detailed study about the robustness of the atomic shell structure in real space

      Kati Finzel

      Article first published online: 18 JUN 2014 | DOI: 10.1002/qua.24724

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      A set of atomic shell indicators is presented based on the idea to express the positive kinetic energy density with a density-based ansatz multiplied by a modifying function. The modifying functions reveal the shell structure and may serve as chemical bonding descriptors. The real space description of the shell structure is very robust with respect to the proposed ansatz since all derived indicators exhibit the atomic shell structure very close to the ideal one.

    3. Factor groups, semidirect product and quantum chemistry

      Marco A. S. Trindade

      Article first published online: 12 JUN 2014 | DOI: 10.1002/qua.24719

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      Symmetries play a fundamental role in quantum chemistry. The rules of spectroscopy, for example, may be derived of the representation of finite groups. In this context, the concept of inner semidirect product can be explored, resulting in the conditions for transitions between energy levels, projection operators, and basis functions.

    4. Density-matrix theory of quantum dynamics under a strong external field switched on nonadiabatically

      H. Kitamura

      Article first published online: 10 JUN 2014 | DOI: 10.1002/qua.24718

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      When a strong, local attractive potential is switched on abruptly to a mesoscopic Fermi gas, the system is driven to a nonstationary state, giving rise to a quantum oscillation. This phenomenon has been demonstrated through the time evolution equations for the density matrix, which are applicable to a wide variety of quantum dynamics from nonadiabatic to adiabatic regime.

    5. The highest oxidation state of Au revealed by interactions with successive cl ligands and superhalogen properties of AuCln (n = 1–6) species

      A. K. Srivastava and N. Misra

      Article first published online: 4 JUN 2014 | DOI: 10.1002/qua.24717

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      The maximum oxidation state of gold (Au) with chlorine ligands is disputed. Quantum chemical calculations show Au that can bind successively up to six Cl atoms forming stable octahedral inline image complex. However, neutral AuCl6 exists in the form of (AuCl4)Cl2 complex, in which Cl2 moiety interacts weakly with the central gold atom. Thus, it can be concluded that the maximum oxidation state of Au does not exceed +5.

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