bluuebunny/crossref_metadata_2025 huggingface dataset:
The crystal structures of two hydrogen monofluorophosphates: CsHPO3F and Cs3(NH4)2(HPO3F)3(PO3F)
Authors: Kemnitz Erhard , Prescott Hillary A. , Troyanov Sergey I.
Published: August 2006

The crystal structures of two new hydrogen monofluorophosphates, CsHPO3F and Cs3(NH4)2(HPO3F)3(PO3F), have been determined at 180 K. The crystals of CsHPO3F are monoclinic, space group C2/m, with the unit cell dimensions of a = 14.478(5) Å, b = 5.929(2) Å, c = 5.413(2) Å, β= 103.30(3)°, V = 452.2(3) Å3, and Z = 4, R1 = 0.0155 and wR2 = 0.0378. Cs3(NH4)2(HPO3F)3(PO3F) crystallizes in the monoclinic space group P21/c, with a = 20.619(4) Å, b = 12.076(2) Å, c = 15.856(3) Å, β= 102.58(2)°, V = 3853(1) Å3, and Z = 8, R1 = 0.0455 and wR2 = 0.0976. In the structure of CsHPO3F, two symmetrically disordered hydrogen bonds (2.527(2) Å) connect two HPO3F units to form closed dimers. Cs3(NH4)2(HPO3F)3(PO3F) contains a complex hydrogen bond network (N-H···O and O-H···O) with two different types of P tetrahedra, PO3F and HPO3F. The structure contains a complex network of hydrogen bonds. Units of 2NH4 and PO3F (I) and Cs and HPO3F (II) are found in and around planes parallel to (x0z). Fluorine is not involved in the hydrogen bonding in either of the structures.
Prediction of crystal structures of two monosaccharides by potential energy minimisation
Authors: Smrcok L'ubomír , Durík M. , Tunega D.
Published: August 2006

Crystal structures of a monoclinic and a hexagonal monosaccharide, 40 atoms per molecule, were successfully predicted by a potential energy minimisation method. The intermolecular interactions were described by three terms covering electrostatic, attraction and repulsion contributions to the total energy. Two types of atomic charges based on the Hartree-Fock wave function, Mulliken and derived from the electrostatic field generated by a molecule, were combined with two force fields called Williams and Dreiding. With the cell parameters fixed, the correct structure was found in approximately 75 % of cases. With the cell parameters optimised no reasonable structure was found for the hexagonal monosaccharide. The accuracy of the predicted structures was evaluated by means of X-ray Rietveld refinements.
Site preference of exchanged alkylammonium ions in heulandite: single-crystal X-ray structure refinements
Authors: Armbruster Th. , Stolz J. , Hennessy B.
Published: August 2006

Single crystals (0.1-0.5 mm) of heulandite, Na0.96K0.09Ca3.54[Al8.62Si27.51O72] · n H2O from Nasik, India, placed in a Teflon autoclave filled with a 2-4 M NaCl solution for 13 weeks at 423 K, yielded Na-exchanged heulandite. CH33NH+-, C2H5NH3+-, n-C3H7NH3
+-, and (CH3)2NH2
+-exchanged heulandites were obtained by further treatment (four weeks at 423 K) with corresponding 1 M alkylammonium chloride solutions. Single-crystal X-ray structure refinements at 293 K of CH3NH3
+-, n-C3H7NH3
+-, and (CH3)2NH2
+-exchanged heulandites performed in space group C2/m yielded R1 values of 3.45%, 4.05%, and 3.99%, respectively. Due to partial Si,Al ordering in the framework C2H5NH3
+-exchanged heulandite was triclinic, space group C-1(R1 = 3.64%). Seven to eight disordered and partly occupied alkylammonium ions per formula unit could be located in the structural channels, except for propylammonium of which for steric and kinetic reasons only traces were incorporated. Infrared powder-spectra and energy-dispersive analyses with a scanning electron microscope confirmed the incorporation of alkylammonium ions. The nitrogen positions of the CH3NH3-, C2H5NH3-, and n-C3H7NH3-molecules corresponded well with the nitrogen positions of NH4
+-exchanged heulandite refined by Yang and Armbruster (1998), while the (CH3)2NH2-ions showed a different arrangement.
Molecular structure and substituent electronic effects in 10-arylidenanthrones-9
Authors: Shishkin O.V. , Kovalevsky A.Yu. , Antipin M. Yu. , Tarakhno Z.N.
Published: August 2006

X-ray structural studies of derivatives of 10-arylidenanthrone-9 containing π-electron donating and withdrawing substituents within arylidene fragment have been carried out. In the crystal the molecules are strongly disflattened with the central dihydrocycles adopting an asymmetric boat conformation. This geometry of the molecules is a result of unfavourable non-valence interactions between atoms at the C=C bond and the hydrogens at the peri-positions of the anthraquinone fragment. Calculations performed by the semiempirical quantum-chemical AM1 method demonstrate that in the gas phase equilibrium geometry of the molecules was similar to that in the crystal. It was shown as well that the central dihydrocycle possesses high conformational flexibility in spite of steric overcrowding in all of the compounds. Electronic effects of the substituents had significant influence only on the arylidene moiety, resulting in different rotation angles of the phenyl group around the C=C exocyclic bond and virtually no effect on the anthraquinone part of the molecules.
Crystal structure determination of 2-oxo-3-benzoyloxazolo[3,2-a]pyridine from X-ray powder data
Authors: Zhukov S.G. , Babaev E.V. , Chernyshev V.V. , Rybakov V. , Sonneveld E.J. , Schenk H.
Published: August 2006

The crystal structure of the mesoionic compound 2-oxo-3-benzoyloxazolo[3,2-a]pyridine (C14NO3H9) has been determined from X-ray powder data using the grid search procedure.

The crystal symmetry is orthorhombic (space group Pna21, a=7,940(1) Å, b=24,562(3) Å, c=5,402(1) Å). The results of Rietveld refinement (Rwp = 11,9%; Rexp = 3,7%) with gradually relaxed bond restrains show that the delocalization of positive charge does not involve the entire pyridine fragment and occurs along the triad N-C-O, whereas the negative charge is localized on the carbon atom.
Crystal structure and thermal characterisation of a theophyllinato Cu(II) complex with benzylamine
Authors: Madarász J. , Bombicz P. , Forizs E. , Czugler M. , Pokol G. , Gál S. , Kálmán A.
Published: August 2006

Diaquabis(benzylamine)bis(theophyllinato)copper(II) (1) was prepared and characterised by FTIR spectroscopy and thermogravimetry. Its molecular structure was determined by single crystal X-ray diffraction. 1 crystallises in triclinic crystal system, space group P-1 (No. 2), a = 8.108(1) Å, b = 9.597(2) Å, c = 11.216(2) Å, α = 82.36(1)°, β = 71.19(1)°, γ = 68.42(1)°. Z = 2, ρ = 1.453 Mg m-3, μ = 0.770 mm -1, R = 0.0546. The copper ion is located at an inversion centre and surrounded by two theophyllinate anions (bound via N7), two benzylamines (bound via N) and two water molecules in an octahedral trans arrangement. The complex molecules are connected forming a chain by hydrogen bonds of the water molecules (to N9 and O6 atoms of neighbouring theophyllinato moieties). No chelation of O6 of the theophyllinato anions to Cu2+ occurs. The thermal loss of water molecules at 120°C results in a structural transformation as indicated by powder XRD. On further heating first the benzylamine molecules are lost, then the theophyllinato moieties are degraded. The final residue is CuO in air at 500°C.
The crystal structure of kukisvumite, Na6ZnTi4(Si2O6)4O4 · 4H2O
Authors: Pasero M. , Merlino St. , Ferro O.
Published: August 2006

The crystal structure of kukisvumite, a rare mineral from Kola peninsula, Russia, has been refined in the Pccn space group with X-ray single-crystal data to R = 0.055. Kukisvumite, ideally Na6ZnTi4(Si2O6)4O4.4H2O, has a = 29.029(4) Å, b = 8.595(1) Å, c = 5.209(1) Å, and Z = 2. Its crystal structure is closely related to that of lintisite; the latter mineral is obtained from kukisvumite through the substitution Zn2+ ∀ = 2 Li+. In the Pccn space group an average structural model is realized, resulting in columns of half-occupied [ZnO4] tetrahedra and in zig-zag chains of half-occupied Na-centered octahedra. The actual structure of kukisvumite would imply a concerted ordering of zinc and sodium in neighbour cells. The polysomatic relationships of kukisvumite with the minerals of the lintisite family are shortly outlined.
The inherent displacive structural flexibility of MxV2O5 framework structures
Authors: Withers Ray L. , Millet P. , Tabira Y.
Published: August 2006

A Rigid Unit Mode (RUM) approach is used to investigate the inherent diplacive structural flexibility of layered and tunnel MxV2O5 framework structures. Characteristic low energy modes of distortion of these framework structures are identified which do not distort the essentially rigid constituent polyhedral units and which enable the framework structures to respond to the local crystal chemistry i.e. to the presence (or absence), as well as positioning, of a range of intercalating cations.
Neutron diffraction study of K4(HSeO4)3(H2PO4). A comparison with X-ray structure
Authors: Troyanov Sergey I. , Morozov I.V. , Reehuis M. , Kemnitz Erhard
Published: August 2006

The neutron single crystal diffraction study of K4(HSeO4)3(H2PO4) at room temperature confirmed the known X-ray structure regarding the positions of the heavier atoms with a full occupation of the central position in one XO4 tetrahedron by a Se atom and a half occupation by Se and P in the other. There are three independent protons participating in i) asymmetric; ii) asymmetric, effectively centered; and iii) symmetric centered hydrogen bonds with O···O distances in the range of 2.512 - 2.561 Å. Two latter H atoms have very elongated ellipsoids of thermal motion along the corresponding hydrogen bonds as distinct from the X-ray structure in which these two H atoms were found to be disordered between two positions each. The system of hydrogen bonds can be described as chains with branches. The structural features are better represented by the formula K4(HSeO4)2[H1.5(Se,P)O4]2.
Determination of conduction paths of semiconducting electrons by bond-valence calculations
Authors: Liebau F.
Published: August 2006

An accuracy of 0.01 Å or better of experimentally determined bond lengths suggests that calculated bond valences higher than 0.06 v.u. are to be considered as representing chemical bonds, and that bond-valence sums are a measure of the effective valence of an atom. Consequently, bond valences and effective atom valences, which can easily be calculated on small personal computers, give information on the electronic structure from which conduction paths can be derived even for chemically and structurally complicated materials. Application of the method to eight semiconducting cetineite-type phases, A6[Sb12O18][SbX3]2[DxY6-y], with A = Na+, K+, Rb+, Sr2+, Ba2+; X = S2-, Se2-; D = Na+, Sb3+, C4+; Y = H2O, OH-, O2-, reveals conduction paths in agreement with experimental observations and sophisticated ab initio calculations.
Structure and spectroscopic properties of hydrogencarbonate containing alumosilicate sodalite and cancrinite
Authors: Gesing Th.M. , Buhl J.-Ch.
Published: August 2006

The preparation of the sodalite Na8[AlSiO4]6·(HCO3)1(CO3)0.5(H2O)2 and cancrinite Na7.6[AlSiO4]6·(HCO3)1.2(CO3)0.2(H2O)2 were carried out in a cold-sealed autoclave using a preheated mixture of γ-Al2O3 and precipitated silica together with NaHCO3 and NaOH. The material was encapsulated in a small silver tube and heated for 48 hours at a pressure of 0.1 GPa. Two different types of crystals remained during this process. From these crystals the structure of both compounds were determined from single crystal diffractometer data. The sodalite Na8[AlSiO4]6(HCO3)1(CO3)0.5(H2O)2: P-43n, a = 903.3(1) pm, V = 0.7370(1) nm3, Z = 2, R = 0.013, wR2 = 0.027 for 242 structure factors and 63 variable positional parameters; the cancrinite Na7.6[AlSiO4]6(HCO3)1.2(CO3)0.2(H2O)2: P63, a = 1272.5(2) pm, c = 517.7(1) pm, V = 0.7260(1) nm3, Z = 2, R = 0.034, wR2 = 0.066 for 845 Fs and 99 variables. Spectroscopic properties were measured with an IR microscope in transmission mode using single crystals polished to a thickness of 30 μm. Both structures are build by corner shared six rings of AlO4 and SiO4 tetrahedra stacked cubic close packed ABCABC for the sodalite and hexagonal close packed ABAB for the cancrinite. The mean Al-O (174.3 pm) and Si-O (161.4 pm) distances for the sodalite and 173.7 pm (Al-O) and 161.8 pm (Si-O) are in good agreement with former structure description of related materials. Hydrogencarbonate and carbonate was found statistically distributed in the sodalite β-cages and in the channels of the cancrinite structure. Whereas for the sodium atoms in the sodalite four different positions are observed, the sodium atoms in the cancrinite structure where found near the threefold axes in the cancrinite ε-cage and on one position in the channel.
Metallradien und Ionenradien
Authors: Trömel Martin , Hübner Sven
Published: August 2006

Metallic radii and ionic radii are correlated by two linear relationships one of which comprises the main group elements and the transition elements of groups 3 up to 7. The other one refers to the elements of groups 8 up to 12. The valences (oxidation states) of the ions involved equal the group numbers of the main group elements of groups 1 up to 4, and 3 in the case of P, As, Sb, and Bi. The apparent valences W of the transition metals obey the rule W = 7 − |G−7| with G = group number. The valences of 19 metals only out of the 30 d-block elements seem to equal these apparent valences.
Surprises in diffuse scattering
Authors: Höffe M. , Baake Michael
Published: August 2006

Diffuse scattering is usually associated with some disorder in the analyzed material. Different kinds of disorder may produce different diffuse scattering - or not. In this letter, we demonstrate some aspects of the variety of diffuse scattering that occurs even in very simple examples, and how unawareness may lead astray.
Pressure effects on the structure of lyotropic lipid mesophases and model biomembrane systems
Authors: Winter Roland , Czeslik C.
Published: August 2006

Lipid systems, which provide valuable model systems for biological membranes, display a variety of polymorphic phases, depending on their molecular structure and environmental conditions. By use of X-ray and neutron diffraction the temperature- and pressure-dependent structure and phase behavior of lipid systems, differing in chain configuration and headgroup structure, have been studied. Besides lamellar phases also nonlamellar phases have been investigated. Hydrostatic pressure has been used as a physical parameter for studying the stability and energetics of lyotropic lipid mesophases, but also because high pressure is an important feature of certain natural membrane environments (e.g., marine biotopes) and because the high pressure phase behavior of biomolecules is of biotechnological interest (e.g., high pressure food processing). We demonstrate that temperature and pressure have noncongruent effects on the structural and phase behavior. By using the pressure-jump relaxation technique in combination with time-resolved synchrotron X-ray diffraction, the kinetics of different lipid phase transformations was also investigated. The time constants for completion of the transitions depend on the direction of the transition, the symmetry and topology of the structures involved, and also on the pressure-jump amplitude. In addition, the effect of incorporating ions, steroids and polypeptides into bilayers on the temperature- and pressure-dependent phase behavior of the lipid systems is discussed.
Bis (3-hydroximinobut-2-one thiosemicarbazone) nickel(II) chloride monohydrate – a complex with NiN4S2 chromophore: a crystallographic evidence of packing stabilisation by two kinds of four fold H-bonded chloride ions
Authors: Kumar Das A. , Seth S. , Kumar Chattopadhyay S.
Published: August 2006

Bis (3-hydroximinobut-2-one thiosemicarbazone) nickel(II), C10H22Cl2N8NiO3S2, exhibits a considerably distorted octahedral NiN4S2 core with two tridentate ligands approximately oriented along their respective meridional planes, forming two fused five - membered rings while binding the Ni2+ ion. The complex crystallised as the monohydrate of its chloride, space group P21/a Z = 4, a = 15.907(3)Å, b = 7.135(2)Å, c = 19.380(3)Å, β= 102.55(2)0. The only intramolecular association in the structure constitutes an interligand oximino proton  oximino nitrogen interaction. Water molecules and chloride anions are found to occupy lattice cavities. The protons attached to the water molecules and the primary amine groups display bifurcated H-bonding interactions. The chloride ions are interactionally tetracoordinated, forming two kinds of extremely distorted H-bonding systems, one pyramidal and the other tetrahedral. Thus, the molecular packing is stabilised by a complicated interactional network.
Experimental and computational structural study of two hindered aminoanthraquinones in crystals and solutions
Authors: Yatsenko A.V. , Paseshnichenko K.A. , Popov S.I.
Published: August 2006

The crystal and molecular structures of 2-methyl-1-methylamino-anthraquinone (I) and 1-methylphenylamino-anthraquinone (II) were studied by the X-ray single-crystal diffraction and the visible spectra of crystalline specimens and their solutions were recorded. The molecule I is closely planar, whereas in the molecule II the amino group is 58° rotated out of the plane of the anthraquinone skeleton. In both structures the molecules pack in stacks. The comparison of experimental and calculated (on the DFT and AM1 levels) molecular structures, together with the comparison of experimental and INDO/S-calculated electronic spectra, give the evidence that molecular conformations (especially for II) change upon transfer from the solid state to solutions, and the π-delocalisation throughout the whole molecule enhances in the solid state.
Gibbs Energies of Transfer of Hydrogen Ion from Water to Tetrahydrofuran + Water Mixtures and Basicity and Structuredness of Aquo-ethers
Authors: Mandal (Karan) Rupasri , Lahiri Sujit Chandra
Published: August 2006

The thermodynamic dissociation constants for isoelectric reaction of the type LH

Attempts have been made to understand the basicity and structuredness of different aquo-ethers (D + H

DME has been found to be structureforming and D has been found to be structure breaking over the whole composition range (0-87 wt% of organic solvent). But THF is slightly structure forming initially but structure breaking above 40 wt%.
Thermal Diffusion of Weak Electrolytes III. The Soret Coefficients of Normal Carboxylic Acids
Authors: Domonkos L. , Liszi J.
Published: August 2006

A conductometric method is described and applied for the determination of the Soret coefficient of normal carboxylic acids in aqueous solutions in order to check a new model described in our previous papers. The Soret cell originally developed by Agar and Turner was applied with only minor modifications. The results show that the deviations between the measured and calculated Soret coefficients are lower than 2.5% except for formic acid (33% in average).
High-Temperature Carbon Particle Formation and Decay in Carbon Suboxide Pyrolysis behind Shock Waves
Authors: Deppe J. , Emelianov A. , Eremin A. , Jander H. , Wagner H.Gg. , Zaslonko I.
Published: August 2006

The formation of carbon particles following the pyrolysis of C
Decomposition of the CF3CO Radical: Pressure and Temperature Dependencies of the Rate Constant
Authors: Tomas A. , Caralp F. , Lesclaux R.
Published: August 2006

The decomposition rate constant of the CF
Ultrafast Proton-Transfer and Coherent Wavepacket Motion of Electronically Excited 1,8-Dihydroxyanthraquinone in Liquid Benzyl Alcohol Solution
Authors: Jethwa J. , Ouw D. , Winkler K. , Hartmann N. , Vöhringer P.
Published: August 2006

Ultrafast pump-probe experiments with a time-resolution of 30 fs have been carried out to explore the non-radiative relaxation dynamics of electronically excited 1,8-dihydroxyanthraquinone (DHAQ) in polar liquid solution. The results are discussed in terms of a Lippincott-Schroeder double-minimum potential along the proton-transfer reaction coordinate for the ground (S
Reactions of Protonated Water Clusters with Chlorine Nitrate Revisited
Authors: Gilligan J.J. , Moody D.J. , Castleman A.W.
Published: August 2006

Potential reaction mechanisms of D
A Thermodynamic Method of Estimating Anharmonic Molecular Densities of States
Authors: Krems R. , Nordholm S.
Published: August 2006

Simple relations between the experimentally observable thermodynamic properties and the molecular density of states are utilized to provide a method of accurate evaluation of the vibrational density of states taking into account both quantum and anharmonic effects. The result is a smooth function of energy that represents a local average of the exact density of states. Alternatively, it is shown that the anharmonic vibrational density of states may, at least for the small molecules NO
Collisional Deactivation of Highly Vibrationally Excited SO2: A Time-Resolved FTIR Emission Spectroscopy Study
Authors: Qin D. , Hartland G.V. , Chen Carl L. , Dai H.-L.
Published: August 2006

Time-resolved Fourier transform IR emission spectroscopy, capable of 10
Transitions in Order and Molecularity with Temperature in Gaseous Metal Oxidation Reactions. The Sb-O2 System
Authors: Cosic B. , Fontijn A.
Published: August 2006

Examples of reactions which are termolecular near room temperature and gradually switch over to complex-forming bimolecular reactions with increasing temperature are discussed. The Sb/O
Quantitative FM Spectroscopy at High Temperatures: The Detection of 1CH2 behind Shock Waves
Authors: Friedrichs G. , Wagner H.Gg.
Published: August 2006

The technique of time resolved frequency modulation (FM) spectroscopy has been shown to provide a very sensitive means to detect small radicals behind shock waves. Features of high temperature FM spectroscopy behind shock waves will be discussed and a general signal conversion procedure to carry out quantitative concentration measurements will be presented.

Using a high modulation frequency, a high modulation index and high total optical power, singlet methylene radicals (

α
A Dielectric Relaxation Study of Lithium Salt Solutions in Dimethylsulfoxide
Authors: Markarian S.A. , Stockhausen M.
Published: August 2006

The dielectric spectra of LiCl, LiClO
Quantitative Determination of Photokinetic Parameters for Reversible Photoisomerizations in Light Scattering Adsorbent-Adsorbates
Authors: Gade R. , Porada Th.
Published: August 2006

Based on an approximate solution of the differential equations describing the rate of a reversible photoisomerization and the attenuation of the actinic light in a powdered adsorbent-adsorbate a method is presented permitting us to predict the irradiation time dependence of the sample reflectance and to determine both the quantum yields of the partial reactions and the absorption coefficients of the reactant and the product from the reflectance-time-curves measured at two different wavelengths. The present method, thus, is an improved version of the peviously reported procedure [1] which enables the quantum yield of a simple photoreaction to be calculated from the initial slope of the R(
Modeling of Hg(II)-Solubility in Binary and Ternary Solutions Containing Na+, K+, Mg2+, Ca2+, H+ and Cl-
Authors: Moog Helge C. , Herbert H.-J.
Published: August 2006

Literature data for the solubility of mercury(II)-chloride in the quinary system Na-K-Mg-Ca-Cl-H
Doppler-free Two-Photon Spectroscopy of Benzene in a Cold Supersonic Beam
Authors: Clara M. , Siglow K. , Neusser H.J.
Published: August 2006

Doppler-free two-photon absorption is demonstrated for cold molecules in a supersonic beam with a spectral resolution of 10 MHz. It was realized using a frequency stabilized tunable external concentric resonator placed within the vacuum chamber and crossed by the molecular beam. The achieved high resolution allows us to resolve single rotational lines in the S
Laser-Induced Reactions on 2.4-nm Colloidal TiO2 Particles in Aqueous Solution: A Study by Time-Resolved Optoacoustic Calorimetry
Authors: Stopper K. , Dohrmann J.K.
Published: August 2006

Laser-pulse induced optoacoustic calorimetry (LIOAC) was applied to study dissipation as heat and temporary storage of light energy absorbed by TiO
Gas-Phase Kinetics of the Self Reactions of the Radicals CH2F and CHF2
Authors: Beiderhase T. , Hack Walter , Hoyermann Karlheinz , Olzmann Matthias
Published: August 2006

Fluorinated hydrocarbon radical-radical reactions in the gas phase have been studied at low pressure (0.5 ≤ p/mbar ≤ 2) and low temperature (253 ≤ T/K ≤ 333) using the discharge flow reactor molecular beam sampling mass spectrometry (MS) technique. Stable and labile species have been detected by MS applying low energy electron impact as well as multiphoton ionisation.

For the combination reaction

CH

the rate coefficient k

CH

is the main channel (k(1b)/k

For the CHF

CHF

the rate coefficient was measured as k

No pressure dependence of k
Apparent Band Shift of Cr3+-Doped Titania as Observed by Photoacoustic and Impedance Spectroscopy
Authors: Wittmer H. , Engeldinger J. , Hempelmann R. , Breuer H.D.
Published: August 2006

Titania (TiO
A New Algorithm for the Numerical Solution of Diffusion Problems Related to the Smoluchowski Equation
Authors: Nickel B.
Published: August 2006

Diffusion-influenced reactions can often be described with simple kinetic models, whose basic features are a spherically symmetric potential, a distance-dependent relative diffusion coefficient, and a distance-dependent first-order rate coefficient. A new algorithm for the solution of the corresponding Smoluchowski equation has been developed. Its peculiarities are: (1) A logarithmic increase of the radius; (2) the systematic use of numerical fundamental solutions w of the Smoluchowski equation; (3) the use of polynomials of up to the 8
Empirical Regularities in the Behaviour of the Critical Constants of Fluid Alkali Metals
Authors: Hensel F. , Hohl G.F. , Schaumlöffel D. , Pilgrim W.-C. , Franck Ernst Ulrich
Published: August 2006

We report new measurements of the densities of the coexisting liquid and vapour phases of the alkali metals K and Na. Comparison of the coexistence curve of K with those of Cs and Rb in reduced form shows that the alkali metals behave very similarly close to the critical temperatures. The experimental values of the critical constants T
Correlation of Adiabatic States between Perturbed Rotor and Renner-Teller Limits for a Closed-Shell Ion + Open Shell Diatom System
Authors: Dashevskaya E.I. , Nikitin E.E.
Published: August 2006

The adiabatic channel interaction potentials for a system charge + dipole-open-shell-quadrupole linear rotor are calculated in the perturbed rotor and slightly anharmonic Renner-Teller limits. In both cases, first order charge-dipole and charge-quadrupole interactions are not additive; this leads to novel expressions for the energy levels. The result can be used in the construction of the adiabatic correlation diagrams between free rotor states with account for the
Coupling Across Bonds: Ab Initio Calculations for the Anharmonic Vibrational Resonance Dynamics of the Coupled OH and CH Chromophores in Trans Formic Acid HCOOH
Authors: Luckhaus D. , Quack M. , Willeke M.
Published: August 2006

We report high level ab initio calculations (treating correlation by second order Møller-Plesset perturbation theory, MP2) of various two-dimensional (2D), three-dimensional (3D) and four-dimensional (4D) normal coordinate subspaces of the full 12D coordinate space of trans formic acid, HCOOH. With the resulting potential and electric dipole hyper-surfaces accurate vibrational variational calculations are carried out using a discrete variable representation (DVR) for the anharmonically coupled modes. The full absorption spectra are calculated and the overtone spectra of the OH chromophore, which clearly dominates the entire absorption spectrum, are analyzed in detail with respect to their anharmonic resonance dynamics. We have investigated the OH/CH stretching coupling, which is an example for a coupling across bonds, in terms of direct and indirect coupling terms. A close resonance coupling of 5
Theoretical Study of the Heats of Formation of SF, FSO, FSO2 and HSO Radicals
Authors: Badenes M.P. , Tucceri M.E. , Cobos Carlos J.
Published: August 2006

Standard heats of formation of SF, FSO, FSO
Dynamics of Benzonitrile, Propylene Carbonate and Butylene Carbonate: the Influence of Molecular Shape and Flexibility on the Dielectric Relaxation Behaviour of Dipolar Aprotic Liquids
Authors: Barthel J. , Buchner R. , Hölzl Ch.G. , Münsterer M.
Published: August 2006

The results of dielectric relaxation experiments on benzonitrile, propylene carbonate and butylene carbonate, performed between 228.15 K and 338.15 K in the frequency range 0.1 ≤ ν /GHz ≤ 89 are presented. The spectra of the three liquids can be formally fitted with two relaxation processes. The long relaxation time, τ
Dissociation Constants of p-Nitroaniline in Mixed Solvents and a Critical Assessment of the Solvent-Sorting Equilibrium Method for the Determination of the Single Ion Gibbs Energy of Transfer of H+ Ion from Aqueous to Aquo Rich Organic Solvents
Authors: Bandyopadhyay G. , Mondal R. , Lahiri Sujit Chandra
Published: August 2006

The dissociation constants of p-nitroaniline (B) (BH+ ⇔ B + H+
) in methanol + water and propan-1-ol + water mixtures have been determined. Due to the presence of -NH2 and -NO2 groups in complimentary para positions, the dissociation constants for p-nitroaniline decrease with increase in percentage of organic co-solvents contrary to those observed in case of aniline, metanitroaniline etc.

A critical assessment of the solvent-sorting equilibrium method using p-nitroaniline as indicator has been made. The method is not suitable to determine the Gibbs energy of transfer of H+ from aqueous to aquo-rich organic solvents.
Investigations on Formation and Structure of MnOx/SiO2 Catalysts
Authors: Patcas F. , Buciuman F.-C.
Published: August 2006

MnOx/SiO2 catalysts with different manganese loadings, prepared by using the pore volume impregnation technique, have been studied by using the temperature-programmed reduction (TPR) and microscopic laser-Raman spectroscopy techniques in order to characterize the dispersion of the manganese on the support and the nature and formation of the manganese oxide species.

A highly inhomogeneous distribution of manganese over the SiO2 surface has been found, consisting of unloaded white surfaces, transition zones, MnOx islands and well crystallized manganese oxide spots. A MnOx-monolayer species has been identified which consisted of Mn2+ and Mn3+ cations bonded together and to the SiO2 support by means of O-atoms. The presence of this phase in the transition zone diminished by increasing the manganese loading of the catalyst and could not be unequivocally identified on the islands and crystal spots, but at the same time the amount of dispersed and crystallized MnO2 and Mn2O3 increased. A model for the formation of MnOx -species is proposed.
Conductometric Studies of Tetraphenyl Arsonium Chloride and Sodium Tetraphenyl Borate in Different Nonaqueous Media
Authors: Bandyopadhyay G. , Lahiri Sujit Chandra
Published: August 2006

The possibility of ion-pair formation of Ph4AsCl, NaBPh4 and NaCl in methanol, ethanol, propan-2-ol and acetonitrile were examined. The compounds were found to be fairly associated in non-aqueous solvents.
Sub Room Temperature Differential Vapor Pressure Osmometry: A Method for the Determination of the Aggregation Number of α-Heterosubstituted Organolithium Compounds and Lithium Amides in Solution
Authors: Dress K.R. , Rölle T. , Wenzel A. , Bösherz G. , Frommknecht N. , Merkel E. , Sauer W.
Published: August 2006

The aggregation number of α-Selenium- and α-Sulfur-substituted organolithium compounds, lithium amides, and transition metal complexes in solution has been determined by sub room temperature differential vapor pressure osmometry. This novel method allows measurements of oxygen, moisture, and temperature sensitive compounds. The aggregation number of these compounds can be determined in THF solutions at 0°C and in diethyl ether solutions at -35°C.
The Thermal Decomposition of NiC2O4·2H2O: An In situ TP-XRD and TGA/FT-IR Study
Authors: Shen B.-R. , Shen H. , Pan Y.-X. , Chen T.-F. , Cai X.-E.
Published: August 2006

The non-isothermal decomposition of NiC
Monochromators for High-Energy Synchrotron Radiation
Authors: Suortti P. , Buslaps T. , Honkimäki V. , Kretzschmer M. , Renier M. , Shukla A.
Published: August 2006

Several monochromators, which are based on the use of cylindrically bent perfect Si crystals, have been constructed at the High Energy X-ray Scattering beamlines of the ESRF. The monochromators provide different focusing conditions, and the energy band-passes are optimized for the needs of different experiments. Formulas are given for calculation of the focal distances, reflectivity curves, and energy distributions. The lay-out of the beamlines follows the Troika concept, where the radiation fan is either split in 3 beams, or the central beam is utilized successively by semi-transparent monochromators to serve three experimental stations simultaneously. The radiation sources are a 7-period permanent magnet asymmetric wiggler and a superconducting wavelength shifter. The critical energies are 45 keV and 96 keV, respectively. The lowest operation energy is 30 keV, and transmission type monochromators have been used up to 1 MeV photon energies. Typical X-ray flux at the sample is 10
Detection of 1CH2 Radicals in Hydrocarbon Pyrolysis Behind Shock Waves Using FM Spectroscopy
Authors: Deppe J. , Wagner H.Gg.
Published: August 2006

Singlet methylene radical (

(1

an extented Arrhenius expression of

and futhermore rate coefficients for

(7)

(11)

and for the intersystem crossing via

(6)

were determined.

The experimental conditions ranged from 1900 to 4000 K with corresponding pressures between 0.23 to 0.54 bar.

The

α(

reflects well the experimental results obtained for the b˜
‘Ultrafast’ Extended to X-Rays: Femtosecond Time-Resolved X-Ray Diffraction
Authors: Linde D. von der , Sokolowski-Tinten K. , Blome Ch. , Dietrich C. , Tarasevitch A. , Cavalleri A. , Squier J. A.
Published: August 2006

For a long time the capability to perform measurements with femtosecond time-resolution belonged exclusively to the domain of optics. However, in the last few years laser-driven X-ray sources have been developed which enable femtosecond time-resolution to be extended to the X-ray regime.
Measurement of White Light Chirp with Kerr Lens
Authors: Roth M. , Feurer T. , Sauerbrey R.
Published: August 2006

The instantaneous transient Kerr lens in a transparent material offers a simple and efficient method to measure the spectrogram of a white light continuum. Even if the kernel of the spectrogram is not known very well, the instantaneous frequency may be extracted with high accuracy. It is shown that the knowledge of the phase modulation of a white light continuum simplifies the design of the prism compressors in a NOPA system. It also makes cross-correlation measurements at different frequencies in white light pump probe experiments obsolete.
The Development of Excimer Laser Technology – History and Future Prospects
Authors: Basting D. , Stamm U.
Published: August 2006

With focus on commercial aspects the paper reviews the historical development and various technological achievements in the field of excimer lasers since their discovery in 1970. The first commercial excimer laser model in the world, the EMG 500 from Lambda Physik was operating at maximum repetition rates of only 20 Hz, whereas today multi kHz excimer lasers as the NovaLine industrial lasers are available. In 2000, Lambda Physik introduced the most powerful commercial excimer laser, the Lambda Steel with 300 W output power having extremely high stability.

In the more than 30 years of excimer lasers their properties have been studied in a multitude of research laboratories at universities, institutes, national laboratories, and industry. In the attempts to reach parameters in the UV never seen before, energies ranging from mJ to kJ, pulse durations from sub μs down to fs, spectral bandwidths from fractions of 1 nm down to less then 0.1 pm, and beam divergence from 10 mrad down to 10 μrad could be demonstrated at the various excimer lasers wavelengts. Over the years various technological achievements like the NovaTube laser chamber technology, the NovaPowerSwitch pulsed power modules and the HaloSafe fluorine and chlorine generators could be made which make the use of excimer lasers simple and user friendly. Recently, the development of DuraTube technology gave a strong push towards the development of high power 157 nm laser technology for microlithography and laser based micro-machining of “difficult” materials as fused silica or teflon.

The paper describes important steps and quantum leaps in developing and improving excimer lasers. Since a large part of excimer laser development was driven by application requirements some applications developed over the years are touched as well – including early photochemistry and dye laser pumping in F. P. Schäfers laboratories. Finally, currently ongoing and for the future expected technological developments are discussed which will strengthen the position of excimer lasers as user friendly work horses in many industrial and research areas.
Variational Approach to the Energetics of Small Polaron Formation and Hopping in Tungsten Oxides
Authors: Koslowski Thorsten
Published: August 2006

In this communication, we apply a recently presented nonperturbative molecular orbital approach (Th. Koslowski,
Geometric Approach to Multiple-Time-Scale Kinetics: A Nonlinear Master Equation Describing Vibration-to-Vibration Relaxation
Authors: Davis M.J. , Skodje R.T.
Published: August 2006

A geometric approach to the study of multiple-time-scale kinetics is taken here. The approach to equilibrium for kinetic systems is studied via low-dimensional manifolds, with an application to a nonlinear master equation for vibrational relaxation. One of our main concerns is the asymptotic (in time) behavior of the system and whether there is a well-defined rate of approach to equilibrium. One-dimensional slow manifolds provide a good means for studying such behavior in nonlinear systems, because they are the analogue of the eigenvector with least negative eigenvalue for linear kinetics.
Detailed Kinetic Investigation of the C2H5+Cl2 Reaction and Analysis of the Reaction of CH3+Cl2 Initiated by H-Atom Contamination at 298K and at Millitorr Pressures
Authors: Dobis O. , Benson S.W.
Published: August 2006

The bimolecular reaction: C
The Rate Constant for the Recombination Reaction Between CF3 and O2 Measured Between 2 and 110 Torr
Authors: Breheny C. , Hancock G. , Morrell C.
Published: August 2006

The rate constant k
Splitting of the Zero Phonon Lines of Indole, 3-Methyl Indole, Tryptamine and N-Acetyl Tryptophan Amide in Helium Droplets
Authors: Lindinger A. , Lugovoj E. , Toennies J.P. , Vilesov A.F.
Published: August 2006

The high resolution vibronic spectra of the S
NMR Study of Self-Association of Acetanilide in Chloroform, Acetone, Acetonitrile and Dimethyl Sulphoxide
Authors: Luo W.-C. , Chen Jenn-Shing
Published: August 2006

The self-association of acetanilide through hydrogen bonding between N-H and O=C in the solvents [
Structure, Diffusivity and Linear Rheology of Sodium Ether Dodecylsulfate in Aqueous Solutions – (I)
Authors: Clancy S.F. , Paradies H.H.
Published: August 2006

Static and dynamic light scattering measurements have been performed on dilute and semidilute solutions of sodium ether dodecylsulfate (sodium laurylethersulfate, RO(CH
Densities, Apparent Molar Volumes, and Interaction Parameters for the Monosaccharide (D-Xylose, D-Arabinose, D-Glucose, D-Galactose)–NaBr–Water Systems at 298.15 K
Authors: Zhuo Kelei , Wang Jianji , Wang H. , Yue Y.
Published: August 2006

Densities have been measured for the monosaccharide (D-xylose, D-arabinose, D-glucose and D-galactose)–NaBr–water solutions at 298.15 K. These data have been used to calculate the apparent molar volumes of these saccharides ( V
Oscillatory Reaction of Bromate-Gallic acid. A Calorimetric and Electrometric Study in Aquo-Organic Solvent Media
Authors: Biswas S. , Mukherjee K. , Basu S.N. , Mukherjee D.C. , Moulik S.P.
Published: August 2006

The oscillatory reaction between potassium bromate and gallic acid (in presence of sulfuric acid and ferroin indicator) has been calorimetrically and potentiometrically studied in binary mixtures of water and organic solvents viz. dimethyl formamide, acetonitrile, tetrahydrofuran and 1,4-dioxan. The effects of solvent polarity, stirring condition, indicator concentration, aerial oxygen and chloride ion on the oscillatory process have been examined. The oscillatory behaviour of the reaction probed by the potentiometric method has a general agreement with the calorimetric method. An attempt has been made to determine the order of the Fe
Adsorption Properties of Silica towards Poly(Ethylene Oxide) as a Function of pH Studied by Spin-Labelling
Authors: Hommel H. , Legrand A.P.
Published: August 2006

Poly(ethylene oxide) chains spin labelled at their free end were adsorbed on amorphous silica and put into contact with buffers of different pH. The Electron Paramagnetic Resonance spectrum has a shape very sensitive to the Brownian motion of the free radical and exhibits composite lines characteristic of two environments: loops and tails protruding into solution with a fast motion; trains adsorbed on the solid surface with a restricted motion. Both components were analysed and the rotational correlation times and the two populations of labels were plotted as a function of pH and temperature. The chains are progressively desorbed as both increase due to the weaker hydrogen bounding with the reactive silanol groups present at the surface. Therefore a molecular picture of the chains at the interface can be gained.
Kinetics and Mechanism of the Homogeneous Oxidation of Quinaldine Red by Hydrogen Peroxide
Authors: Salem Ibrahim A. , El-Maazawi M.
Published: August 2006

The kinetics of the oxidation of quinaldine red, a cationic dye, using hydrogen peroxide has been studied in aqueous solution. The rate of reaction was found to be first order in [quinaldine red] whereas in hydrogen peroxide it varies from one to zero with increasing [H
Interactions in Sphere Packings
Authors: Hauck J. , Mika K.
Published: August 2006

The circle packings including non-periodic packings and 41 homogeneous sphere packings with 4≤ T
Picosecond IR Study of UV-Induced Peroxide Decomposition: Formation and Vibrational Relaxation of CO2 in CH2Cl2 Solution
Authors: Buback Michael , Kling M. , Seidel M.Th. , Schott F.D. , Schroeder J. , Steegmüller U.
Published: August 2006

Picosecond UV pump (248.5 nm)/IR probe spectroscopy has been applied to the study of the decomposition of several aromatic diacyl peroxides, peroxycarbonates, and of a peroxyester dissolved in CH
Two-Photon Spectroscopy of Jet-Cooled Benzonitrile: New Results for a Charge Transfer Molecule
Authors: Clara M. , Siglow K. , Neusser H.J.
Published: August 2006

We compare the first jet-cooled two-photon fluorescence excitation spectrum of benzonitrile with its one-photon spectrum measured by resonance-enhanced multi-photon ionization (REMPI). Both spectra include the pure electronic transition and one vibrationally induced transition. The inducing mode is the ν
Experimental and Modelling Study of 1-Pentene Combustion at Fuel-Rich Conditions
Authors: González Alatorre G. , Böhm H. , Atakan Burak , Kohse-Höinghaus Katharina
Published: August 2006

A fuel-rich, non-sooting (C/O = 0.773) 1-pentene/oxygen/argon flame is studied experimentally at 50 mbar. The results are compared to computations. The calculations show satisfactory agreement with the data obtained from the measurements. The main channels for 1-pentene decomposition are presented and discussed in view of previous data for a propene flame at similar experimental conditions. Special emphasis is directed towards the formation of the first aromatic ring and the further growth of small aromatic hydrocarbons. By reaction flow analysis, it is found that the major reaction channel for benzene formation results from the recombination of propargyl radicals. Furthermore, the major reaction channels for naphthalene formation are presented.
Product state distribution and stereodynamics of the O(1D) + N2O reaction
Authors: Akagi H. , Tsurumaki H. , Fujimura Y. , Kajimoto O.
Published: August 2006

The vibrational state distribution and the stereodynamics of product NO in the highly exothermic O(
CH4 Deep Oxidation on Ag Promoted Manganese Oxide Catalysts
Authors: Wang H. , Xie G.
Published: August 2006

Manganese oxide modified by various amounts of Ag was prepared and used for CH
The Collisional Behaviour of Ba[6s5d(3DJ)] Generated Following Pulsed Dye-Laser Excitation at λ = 553.5 nm {Ba[6s6p(1P1)] ← Ba[6s2(1S0)]} in the Presence of Noble Gases and Ground State Atomic Barium by Atomic Spectroscopic Marker Emission Measurements in the Time-Domain
Authors: Adams J.W. , Lei J. , Husain D.
Published: August 2006

We present a kinetic study of the collisional behaviour of Ba[6
Evolution in Systems of Ligation-Based Replicators
Authors: Stadler Bärbel M. R. , Stadler Peter F. , Wills Peter R.
Published: August 2006

The population dynamics of macromolecules that reproduce by means of template-directed ligation of two fragments are shown to be represented by a replicator equation with a special non-linear response function. This result is obtained through detailed consideration of the mechanism of ligation autocatalysis. In contrast to treatments which involve simplification to a parabolic growth law and the expectation of global coexistence of all species, we find that strong selection can take place in such systems, even when there is slow uncatalysed synthesis of replicators. Also, systems of this type are subject to invasion by new species that have a selective advantage. An expression is derived for the survival threshold in terms of species parameters and it is shown that this threshold depends on the total concentration of all species in the system. For a plausible distribution of species parameters, the number of surviving species coexisting above the threshold increases monotonically with increasing concentration. Illustrative numerical simulations are presented.
Competitive Exclusion of Disjoint Hypercycles
Authors: Hofbauer Josef
Published: August 2006

A conjecture of Eigen and Schuster (1979) concerning the competitive exclusion of disjoint hypercycles is finally proved.
Multilevel Evolution: The Fate of Duplicated Genes
Authors: Hogeweg Paulien
Published: August 2006

Biological evolution is a multilevel process and should be studied as such. A first, important step in studying evolution in this way has been the work of Peter Schuster and co-workers on RNA evolution. For RNA the genotype-phenotype mapping can be calculated explicitly. The resulting evolutionary dynamics is dominated by neutral paths, and the potential of major change by a single point mutation.

Examining whole genomes, of which about 60 are now available, we see that gene content of genomes is changing relatively rapidly: gene duplication, gene loss and gene generation is ubiquitous. In fact, it seems that point-mutations play a relatively minor role, relative to changes in gene regulation and gene content in adaptive evolution.

Large scale micro-array studies, in which the expression of every gene can be measured simultaneously, give a first glimpse of the `division of labor´ between duplicated genes. A preliminary analysis suggests that differential expression is often the primary event which allows duplicated genes to be maintained in a genome, but alternate routes also exist, most notably on the one hand the mere need of a lot of product, and on the other hand differentiation within multi-protein complexes consisting of homologous genes.

I will discuss these results in terms of multilevel evolution. in particular in terms of information integration and the alternatives of `individual based´