ChemPhysChem

Cover image for Vol. 7 Issue 8

August 11, 2006

Volume 7, Issue 8

Pages 1605–1830

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. Review
    5. Minireview
    6. Communications
    7. Articles
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    1. Cover Picture: Glass Bead Probes of Local Structural and Mechanical Properties of Fluid, Supported Membranes (ChemPhysChem 8/2006) (page 1605)

      Sanhita S. Dixit, Alan Szmodis and Atul N. Parikh

      Article first published online: 3 AUG 2006 | DOI: 10.1002/cphc.200690026

      The cover picture shows a spatial pattern of morphology-dependent elastic response of supported membranes to gravitationally settled microscopic glass beads. Beads differentiate lipid monolayers (red regions) from fluid bilayers (yellow regions) by inducing a qualitatively different elastic response, characterized by nondeformed binding for lipid monolayers (uncoated beads) and a wetting or membrane wrapping for bilayers (membrane wrap enveloping the beads). These results presented by Parikh et al. on page 1678 indicate the importance of interleaflet coupling and bilayer fluidity in determining elastic response of supported membranes. They also suggest a new, simple technique to probe mechanical properties of substrate-supported fluid membranes. The art work was designed by James Evans.

  2. Graphical Abstract

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    3. Graphical Abstract
    4. Review
    5. Minireview
    6. Communications
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    1. Graphical Abstract: ChemPhysChem 8/2006 (pages 1607–1616)

      Article first published online: 3 AUG 2006 | DOI: 10.1002/cphc.200690027

  3. Review

    1. Top of page
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    3. Graphical Abstract
    4. Review
    5. Minireview
    6. Communications
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    1. One Hundred Years of Light Quanta (Nobel Lecture) (pages 1618–1639)

      Roy J. Glauber

      Article first published online: 3 AUG 2006 | DOI: 10.1002/cphc.200600329

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      The Nobel Prize in Physics 2005 falls in the realm of light (see picture; a) classical and b) quantum physics observation of light), and it is awarded to three scientists: Roy Glauber, John Hall and Theodor Hänsch. Roy Glauber succeeded in describing a general method for observing photons. He formulated a theory that gives optics a quantum-mechanical basis.

  4. Minireview

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    3. Graphical Abstract
    4. Review
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    6. Communications
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    1. DNA Tile Based Self-Assembly: Building Complex Nanoarchitectures (pages 1641–1647)

      Chenxiang Lin, Yan Liu, Sherri Rinker and Hao Yan

      Article first published online: 10 JUL 2006 | DOI: 10.1002/cphc.200600260

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      Smart structures: DNA tile based self-assembly provides an attractive route to create nanoarchitectures of programmable patterns (see figure). It also offers excellent scaffolds for directed self-assembly of nanometer-scale materials ranging from nanoparticles to proteins, with potential applications in constructing nanoelectronic/nanophotonic devices and protein/ligand nanoarrays.

  5. Communications

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    2. Cover Picture
    3. Graphical Abstract
    4. Review
    5. Minireview
    6. Communications
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    1. Design of a Molecular Quasicrystal (pages 1649–1653)

      Zhongfu Zhou and Kenneth D. M. Harris

      Article first published online: 3 AUG 2006 | DOI: 10.1002/cphc.200600278

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      Designer materials: The authors propose a design strategy for a quasicrystalline material composed of discrete molecular entities. The molecular quasicrystal (see figure), which is based on a standard Penrose tiling, is energetically stable and gives rise to a 10-fold symmetric diffraction pattern. The strategy may be further exploited to design molecular quasicrystals based on a range of different types of quasiperiodic arrays.

    2. A Joint Theoretical–Experimental Investigation of the Faraday Effect in Benzene, Toluene, and p-Xylene (pages 1654–1656)

      Edith Botek, Benoît Champagne, Thierry Verbiest, Palash Gangopadhyay  and André Persoons 

      Article first published online: 14 JUL 2006 | DOI: 10.1002/cphc.200600221

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      Dispersion of the Verdet constant is determined experimentally and theoretically for benzene, toluene, and p-xylene as pure liquids. Both theory and experiment show that the amplitude of the Verdet constant decreases when methyl groups are added to the benzene ring, due to the decreasing number density with the increasing size of the molecule. The picture shows the Verdet constants of benzene, toluene, and p-xylene as a function of wavelength and compares theory with experiment.

    3. The Conformations of Alkanes Adsorbed on Zeolitic Cations (pages 1657–1660)

      Evgeny A. Pidko and Rutger A. van Santen

      Article first published online: 27 JUN 2006 | DOI: 10.1002/cphc.200600276

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      Size governs conformation: Adsorption of light alkanes to Mg and Ca cations exchanged in faujasite is studied by ab initio calculations and topologic analysis of electron density distribution functions. The conformation of the adsorbed alkanes depends on the cation, due to differences in bonding within the adsorption complexes controlled by the size of the exchanged cation.

    4. Remarkably Stable Icosahedral Fulleranes: C80H80 and C180H180 (pages 1661–1663)

      Mikko Linnolahti, Antti J. Karttunen and Tapani A. Pakkanen

      Article first published online: 20 JUL 2006 | DOI: 10.1002/cphc.200600302

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      Spherical hydrocarbons: Perhydrogenation of icosahedral fullerenes, C80 and C180, produces remarkably stable C80H80 and C180H180 fulleranes (see picture). The authors show that the controlled synthesis of the fulleranes opens up a new branch of chemistry through their functionalization.

    5. The Origin of Systematic Error in the Standard Enthalpies of Formation of Hydrocarbons Computed via Atomization Schemes (pages 1664–1667)

      Gyula Tasi, Róbert Izsák, Gergely Matisz, Attila G. Császár, Mihály Kállay, Branko Ruscic and John F. Stanton

      Article first published online: 14 JUL 2006 | DOI: 10.1002/cphc.200600224

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      Update required! The differences between dependable computed and experimental enthalpies of formation of larger hydrocarbons, growing systematically with size, are traced to an about 0.5 kJ mol−1 error in the canonical best estimate of the enthalpy of formation of atomic carbon (see figure). The results obtained in this study call for an update of Δfequation image(Cgas).

    6. Molecular-Recognition and Binding Properties of Cyclodextrin-Conjugated Polyrotaxanes (pages 1668–1670)

      Hak Soo Choi, Akihiro Takahashi, Tooru Ooya and Nobuhiko Yui

      Article first published online: 28 JUN 2006 | DOI: 10.1002/cphc.200600147

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      Sliding and rotation of cyclodextrins (CDs) along the polymer main chain of polyrotaxanes significantly increases the binding ability for and molecular recognition of guest molecules by multifaceted inclusion complexation (see schematic diagram). The cyclodextrin-conjugated polyrotaxanes were obtained by attaching β-CDs to an α-CD/poly(ethylene glycol) polyrotaxane backbone via peptide bonds.

    7. pH-Sensitive Locomotion of Cyclodextrins in a Block–Selective Mobile Polyrotaxane (pages 1671–1673)

      Hak Soo Choi , Ayaka Hirasawa, Tooru Ooya , Daisuke Kajihara, Takahiro Hohsaka and Nobuhiko Yui 

      Article first published online: 10 JUL 2006 | DOI: 10.1002/cphc.200600242

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      On the move! A block-selective mobile polyrotaxane, synthesized in a one-pot sequence using anthracene (AN) capping agents, examines the movement of α-cyclodextrins (α-CDs) along the chains of a PEI-b-PEG-b-PEI copolymer (see figure). By labeling the α-CDs with fluorescein (FL) and monitoring the fluorescence resonance energy transfer, the intramolecular block-selective movement of α-CDs is characterized in response to pH variation.

    8. A Novel Approach to Stable Superhydrophobic Surfaces (pages 1674–1677)

      Zhi-Guang Guo, Jian Fang, Jing-cheng Hao, Yong-min Liang and Wei-min Liu

      Article first published online: 17 JUL 2006 | DOI: 10.1002/cphc.200600217

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      Nature calls: The lotus leaf is held as a symbol of purity due to its ability to remain clean after emerging from murky ponds. Its superhydrophobic surface, which removes undesired particles in water droplets, is mimicked by a simple and inexpensive method involving self-generation of superhydrophobic films on copper substrates. The resulting films (water contact angle of 170±1.6°, see picture) show good self-cleaning properties.

    9. Glass Bead Probes of Local Structural and Mechanical Properties of Fluid, Supported Membranes (pages 1678–1681)

      Sanhita S. Dixit, Alan Szmodis and Atul N. Parikh

      Article first published online: 17 JUL 2006 | DOI: 10.1002/cphc.200600222

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      Probing membranes: Nonspecific interactions between glass beads and supported lipid membranes act as a simple tool to characterize their local structure and mechanical properties. The beads differentiate monolayers (see figure B) from fluid bilayers (A) by inducing a qualitatively different elastic response, characterized by undeformed binding for monolayers and membrane wrapping for bilayers.

    10. Velocity Map Imaging Study of the Photodissociation of CH3SH: Internal Energy Distribution of the SH Fragment (pages 1682–1686)

      Jesús G. Izquierdo, Gabriel A. Amaral, Florian Ausfelder, F. Javier Aoiz and Luis Bañares

      Article first published online: 29 JUN 2006 | DOI: 10.1002/cphc.200600232

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      Energy breakdown: Photodissociation of mercaptan in the second absorption band has been studied by velocity map imaging. CH3 fragment images (see figure) show a structure directly related to the vibrational population of the SH counterfragment. An inverted SH vibrational population has been measured suggesting a non-adiabatic fast photodissociation.

    11. Surface Properties and Photocatalytic Activity of Ptcore/Agshell Nanoparticle-Loaded TiO2 (pages 1687–1691)

      Hiroaki Tada, Ayako Takao, Tomoki Akita and Koji Tanaka

      Article first published online: 17 JUL 2006 | DOI: 10.1002/cphc.200600261

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      Bimetallic nanoparticles are successfully formed on the surface of TiO2 (see figure) with Ag shell layer (nL) control. Pt@Ag/TiO2 exhibits unique photocatalytic performances for reduction of nitorobenzene at nL≤1, however when nL exceeds ≈1 they are similar to those of Ag/TiO2. Furthermore at the critical value of nL≈1, the surface properties of Pt@Ag nanoparticles change from Pt to Ag.

  6. Articles

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. Review
    5. Minireview
    6. Communications
    7. Articles
    8. Book Reviews
    9. Preview
    1. Influence of Electric Field on the Phase Transitions of the Hexagonal Cylinder Phase of Diblock Copolymers (pages 1693–1698)

      Xin Li, Ying Jiang, Yinchang Li and Haojun Liang

      Article first published online: 10 JUL 2006 | DOI: 10.1002/cphc.200500725

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      Simulations reveal order: Cell dynamic simulations probe the evolution of asymmetric and symmetric diblock copolymers under electric fields. The results suggest that the sphere phase is stable under weak electric fields, but a threshold electric intensity exists for the sphere-to-cylinder phase transition (see figure).

    2. Single-Molecule Dynamic Triangulation (pages 1699–1704)

      Taras Plakhotnik

      Article first published online: 27 JUN 2006 | DOI: 10.1002/cphc.200600028

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      Nanoprobes: Single molecules, used as nanoprobes to detect elementary charge trajectories, provide a three dimensional single-electron displacement within a few seconds with an accuracy better than 0.006 nm (figure shows simplified 1-D triangulation of an electron). This significantly exceeds the accuracy with which the probe molecule itself can be localized in the same measuring time by single-molecule microscopy.

    3. Specific Vectorial Immobilization of Oligonucleotide-Modified Yeast Cytochrome c on Carbon Nanotubes (pages 1705–1709)

      Hendrik A. Heering, Keith A. Williams, Simon de Vries and Cees Dekker

      Article first published online: 28 JUN 2006 | DOI: 10.1002/cphc.200600108

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      A selective interface: The specific modification of Cys102 with dT18 provides a tether to the single-walled carbon nanotube (SWNT) sidewall, resulting in an orientation of yeast cytochrome c (YCC) that facilitates docking of redox enzymes and subsequent electron transfer (see figure). Oligonuclotide-modified YCC on a SWNT thus provides a selective interface between nanoscopic electronic devices and complex enzymes.

    4. Viscoelastic Properties of Single Poly(ethylene glycol) Molecules (pages 1710–1716)

      Masaru Kawakami, Katherine Byrne, Bhavin S. Khatri, Tom C. B. McLeish and D. Alastair Smith

      Article first published online: 25 JUL 2006 | DOI: 10.1002/cphc.200600116

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      Single-molecule mechanics: The dynamic response of single polymer chains to an oscillatory applied force is reported. Viscoelastic properties can be extracted from both thermally and magnetically forced motion. The figure shows a schematic representation of the conformational changes of the poly(ethylene glycol) molecule and how these relate to the dependence of the internal friction on the applied force.

    5. Ultrafast Photoisomerization of Photoactive Yellow Protein Chromophore Analogues in Solution: Influence of the Protonation State (pages 1717–1726)

      Agathe Espagne, Daniel H. Paik, Pascale Changenet-Barret, Monique M. Martin and Ahmed H. Zewail

      Article first published online: 17 JUL 2006 | DOI: 10.1002/cphc.200600137

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      The importance of being negative: The primary photochemistry of the photoactive yellow protein (PYP), a photoreceptor for bacterial photomotility, relies on the trans–cis photoisomerization of its anionic p-coumaric acid chromophore. The authors investigate the influence of the protonation state of ester and ketone derivatives (see figure) of the PYP chromophore on the photoisomerization pathway in solution.

    6. The Excited-State Chemistry of Protochlorophyllide a: A Time-Resolved Fluorescence Study (pages 1727–1733)

      Benjamin Dietzek, Wolfgang Kiefer, Arkady Yartsev, Villy Sundström, Peter Schellenberg, Paulius Grigaravicius, Gudrun Hermann, Jürgen Popp and Michael Schmitt

      Article first published online: 14 JUL 2006 | DOI: 10.1002/cphc.200600172

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      Model refinement: The excited-state chemistry of protochlorophyllide a, the precursor of chlorophyll a by means of picosecond time-resolved fluorescence (see figure) is discussed. A detailed spectral characterization of the emission significantly refines the kinetic model deduced from ultrafast absorption measurements in terms of a branching of the initial excited-state population into a reactive and a nonreactive path.

    7. Vibrational Structure of Endohedral Fullerene Sc3N@C78 (D3h): Evidence for a Strong Coupling between the Sc3N Cluster and C78 Cage (pages 1734–1740)

      Matthias Krause, Alexey Popov and Lothar Dunsch

      Article first published online: 3 AUG 2006 | DOI: 10.1002/cphc.200600139

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      Covalent fixation in cluster fullerenes: FTIR, Raman and DFT analysis show that a strong covalent Sc3N–C78 cage interaction determines the vibrational structure of the Sc3N@C78 cluster fullerene. The authors show that an ionic interaction between separated Sc3N6+ and C786− ions does not account for the geometric and vibrational properties (see picture for geometric structure).

    8. Theoretical Dynamic Studies on the Reaction of CH3C(O)CH3−nFn with the Hydroxyl Radical and the Chlorine Atom (pages 1741–1749)

      Yue-Meng Ji, Li Wang, Ze-sheng Li, Jing-yao Liu and Chia-chung Sun

      Article first published online: 3 AUG 2006 | DOI: 10.1002/cphc.200600143

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      Hydrogen abstraction: The mechanisms of the reactions: CH3C(O)CH2F+OH/Cl[RIGHTWARDS ARROW]products (R1/R2) and CH3C(O)CF3+OH/Cl[RIGHTWARDS ARROW]products (R3/R4) (see figure) were studied over a wide temperature range (200–2000 K) using the dual-level direct dynamics method. The results indicate that the hydrogen abstraction predominantly takes place at the fluoromethyl position.

    9. Electrochemically Driven Three-Phase Interlines into Insulator Compounds: Electroreduction of Solid SiO2 in Molten CaCl2 (pages 1750–1758)

      Wei Xiao, Xianbo Jin, Yuan Deng, Dihua Wang, Xiaohong Hu and George Z. Chen

      Article first published online: 29 JUN 2006 | DOI: 10.1002/cphc.200600149

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      Electrolysis on an insulator (see figure, a) is conducted in molten CaCl2 (1173 K) to produce a conductor (see figure, b). The process takes place following the predictions of a novel model, which is based on electrochemical reactions at the dynamic insulator|conductor|electrolyte three-phase interlines.

    10. Effect of the Complexant Shape on the Large First Hyperpolarizability of Alkalides Li+(NH3)4M (pages 1759–1763)

      Ying-Qi Jing, Zhi-Ru Li, Di Wu, Ying Li, Bing-Qiang Wang, Feng Long Gu and Yuriko Aoki

      Article first published online: 25 JUL 2006 | DOI: 10.1002/cphc.200600157

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      High complexant symmetry is an important factor that should be taken into account when enhancing the first hyperpolarizability β0 of alkalides by chemical doping. Thus, β0 values of Li+(NH3)4M (M=Li, Na, K) with the Td-symmetric (NH3)4 complexant are more than four times larger than those of Li+(calix[4]pyrrole)M with the C4v-symmetric complexant. The picture shows the 0.035 isosurfaces of the HOMO in Li+(NH3)4M.

    11. New Experimental and Theoretical Results for Argon Broadening and Shift of HCO+ Rotational Lines (pages 1764–1769)

      Giovanni Buffa, Luca Dore, Francesca Tinti and Markus Meuwly

      Article first published online: 10 JUL 2006 | DOI: 10.1002/cphc.200600166

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      Revelations into the interstellar world: The Ar–HCO+ complex is under investigation to test and validate current computational methods for obtaining reliable pressure broadenings and shifts. Measurements are carried out at 77 K and are compared to close-coupling calculations performed on a potential energy surface (see figure) accounting for interactions extending from small to very large separations between the ion and the perturber.

    12. Growing Graphene Sheets from Reactions with Methyl Radicals: A Quantum Chemical Study (pages 1770–1778)

      Yannick Carissan and Wim Klopper

      Article first published online: 25 JUL 2006 | DOI: 10.1002/cphc.200600171

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      Growing pains: Hydrogen abstraction reactions by methyl radicals on the zigzag and armchair edges of perylene (see picture) are studied by density functional theory to explore the various growth pathways. The results obtained with six different functionals are compared with those from ab initio methods. A cascade of reactions is possible that leads to the growth of a graphene sheet on a graphite surface.

    13. The Gas-Phase Chemistry of cis-Diammineplatinum(II) Complexes: A Joint Experimental and Theoretical Study (pages 1779–1785)

      Andreas Springer, Christian Bürgel, Verena Böhrsch, Roland Mitrić, Vlasta Bonačić-Koutecký and Michael W. Linscheid

      Article first published online: 17 JUL 2006 | DOI: 10.1002/cphc.200600177

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      Unexpected fragments: Solvolysis products of the anticancer drug cisplatin [PtII(NH3)2Cl2] are investigated by mass spectrometry and density functional calculations. The picture shows collision-activated fragmentation of [PtII(NH3)2(CH3OH)Cl]+ with loss of water. The corresponding reaction profile showing transition states (TS) and intermediates is depicted inside the mass spectrum.

    14. A Theoretical Study of the Mechanism and Kinetics of F+N3 Reactions (pages 1786–1794)

      Haitao Ma, Xiaojun Liu, Wensheng Bian, Lingpeng Meng and Shijun Zheng

      Article first published online: 3 AUG 2006 | DOI: 10.1002/cphc.200600183

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      Two typical cuts in the singlet and triplet potential energy surfaces of F+N3 reactions around the region of the minimum energy crossing point (MECP) at the intersection seam and the singlet transition state are shown in the figure, which is used to clarify the reaction mechanism. The authors demonstrate that the adiabatic reaction leading to NF(a1Δ) is the major channel, whereas the nonadiabatic reaction through the MECP—which leads to NF(X3Σ)—is a minor channel.

    15. Theoretical Study of N2O Reduction by CO in Fe-BEA Zeolite (pages 1795–1801)

      Gerd Fischer, Annick Goursot, Bernard Coq, Gérard Delahay and Sourav Pal

      Article first published online: 17 JUL 2006 | DOI: 10.1002/cphc.200600228

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      Catalytic cycle: A large quantum mechanical (QM) cluster is used to investigate the role of Fe-BEA zeolites (see figure) in the reduction of nitrogen oxides. The use of a large cluster accounts for several diffusion pathways in the zeolites which lead to different activation barriers. The theoretical results for the full catalytic cycle (oxidation and reduction) compare favorably to experimental values.

    16. Surface Composition of Materials Used as Catalysts for Methanol Steam Reforming: A Theoretical Study (pages 1802–1812)

      Kok Hwa Lim, Lyudmila V. Moskaleva and Notker Rösch

      Article first published online: 28 JUN 2006 | DOI: 10.1002/cphc.200600262

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      Modeling methanol steam reforming: The chemical composition of PdZn(111) and Cu(111) in contact with water and hydrogen under pertinent reaction conditions (see figure; pH2=partial pressure of hydrogen, γ=surface energy) are studied as models for catalysts of methanol steam reforming surface. Using thermodynamic analysis based on density functional calculations, the most favorable surface compositions for a given pH2 are determined.

    17. Gas-Phase Reactions of Atomic Lanthanide Cations with D2O: Room-Temperature Kinetics and Periodicity in Reactivity (pages 1813–1819)

      Ping Cheng, Gregory K. Koyanagi and Diethard K. Bohme

      Article first published online: 29 JUN 2006 | DOI: 10.1002/cphc.200600248

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      Lanthanide cations react with D2O at room temperature in a helium bath at 0.35 Torr by O-atom transfer, OD transfer and D2O addition. D2O is not highly reactive towards lanthanide cations and is less reactive than aliphatic alcohols and phenol. The reactivities of all these molecules exhibit a periodic variation across the lanthanide series (see picture; k=rate coefficient, kc=capture or collision rate coefficient).

    18. Significant Reduction of On-Site Coulomb Energy U due to Short-Range Correlation in an Organic Mott Insulator (pages 1820–1824)

      Kaoru Ohno, Yoshifumi Noguchi, Toshihiro Yokoi, Soh Ishii, Jun Takeda and Miou Furuya

      Article first published online: 7 JUL 2006 | DOI: 10.1002/cphc.200600144

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      Influential short range: In a Mott insulator of the organic radical 1,3,5-trithia-2,4,6-triazapentalenyl (TTTA), the two-electron probability distribution (see figure) obtained by first-principles (multiple scattering) T matrix calculations, indicates clearly the formation of a “Coulomb hole”. This short-range electron correlation reduces significantly the on-site Coulomb energy.

  7. Book Reviews

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    3. Graphical Abstract
    4. Review
    5. Minireview
    6. Communications
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      Article first published online: 3 AUG 2006 | DOI: 10.1002/cphc.200690028

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