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Subpicosecond fluorescence anisotropy decay curves are measured using the fluorescence up-conversion technique to examine the rotational dynamics of coumarin 153 (C153) in supercritical fluoroform (T=302 and 310 K). The magnitude of the local density augmentation estimated from the rotation times is in a good agreement with those deduced from the steady-state spectral shifts.

The Raman measurements and density functional theory (DFT) calculations are used to analyze the propensity of pentaerythritol tetranitrate (PETN) to conformational changes. The results revealed that DFT calculations indicated changes in conformation/symmetry is observed through changes in the vibrational spectrum, whereas, the calculated Raman spectra provides support for the conclusion that the S4 symmetry, at ambient conditions, changes to C2 under static high-pressure loading and to C2 or C1 in solution.

A study was conducted to analyze the hydrogen bonds, proton affinity, and pKa values of the N-formyl-L-histidinamide model system with respect to all possible conformers. The results revealed that the protonation state of histidines on the surface of a protein depends primarily on the pH, whereas, due to protonation or deprotonation, the side-chain and/or backbone orientation of these histidine residues may undergo considerable changes.

The phosphate ions HPO4(super 2-) and H2PO4(super -1) are analyzed since sizable solvation effects are expected for the IR spectra of these strongly polarizable ions. The widths, intensities, and spectral positions of the resultant bands are compared with experimental IR spectra for the purpose of checking the computational procedures, which provide insights into the merits and limitations of the available density functional theory (DFT)/molecular mechanisms (MM) approach to the prediction of IR spectra in the condensed phase.

The cleavage reactivity of compounds containing a leaving group illustrated by the carbon-halogen bond cleavage reaction in haloaromatic anion radicals are determined with three different ionic liquids. The results reported that large modifications depended on the localization of the negative charge in the radical anions and, to a lesser extent, on the nature of the ionic liquids cations.

The mixed dimers 2-pyridone.uracil(2PY.U), 2-pyridone.thymine(2PY.T), and 2-pyridone.5-florouracil(2PY.5-FU) are investigated, in which 2PY acts as the UV chromophore, avoiding the photophysical drawbacks of U, T, and 5-FU as shown by theoretical investigations, 2-pyridone forms only two H-bonds, which restricts the number of isomers to only three. The results revealed that the comparison of the spectra of 2PY.U, 2PY.T, and 2PY.5-FU allows determining the effects of methylation and fluorination on the ground- and excited-state binding energies, vibrational frequencies, and intermolecular forces.

The hydration properties and the self-aggregation of tert-butyl alcohol (TBA) in water are analyzed by comparing them with those of the isostretic molecule trimethylamine-N-oxide (TMAO), which has the same alcohol hydrophobic part and a different polar head. The results revealed that the whole water molecules are more tightly coordinated by TMAO than by TBA.

Various dihydrogen-bonded complexes involving H..H contacts have been studied. It was concluded that DHBS are in line with the findings of hydrogen bonds, and that hydrogen bridges are interactions without borders.

It is shown that the loss of species on the reactor wall has to be taken into account while analyzing the kinetic results of the droplet-train apparatus. The uncertainty of the extracted gas-surface reaction and the probability for high water vapor experimental conditions have increased due to the revision of the kinetics for species with a wall loss.

The m-cyanobenzyl radical was generated in the jet from m-tolunitrile seeded in a large amount of helium carrier gas and vibronically excited in a corona excited supersonic expansion by using the modified Engelking-type nozzle. The accurate vibrational mode frequencies were obtained in the ground electronic state by analyzing the spectrum.

The results of CH...F H-bonds of various types, as well as the depth of the minima and energetic of interconversion are analyzed. It concluded that the global minimum of the fluoroform dimer appears to have a usual structure, which is of general donor-acceptor type, but one of the H-bonds is bifurcated.

The reaction between the hydroxide ion and ethyl acetate in two different solvents such as water and dimethyl sulfoxide (DMSO) solutions are presented with the help of ab initio calculations. The results suggest that the elimination mechanism could become the dominant pathway in the basic hydrolysis of sterically crowded esters at the carbonyl center.

An investigation on the interaction of compensatory and noncompensatory solutes with water is analyzed by several computational methods. The findings indicate that there is no difference in their effect on water structure between compensatory solutes and urea, but there are distinct differences with the noncompensatory solute DMSO.

The vibrational analysis with a lumped-inertia technique can efficiently and reliably anticipated certain vibrational properties without the need for performing costly comprehensive full normal-mode computations is demonstrated. The model affords a portioning of the effect of phenyl ring substituents on the torsional vibrational frequencies between inertial and electronic structure contributions.

A competitive electron transfer from the S2 and S1 states of ZnTPP-PI and ZnTPP-Beta-PhPI in 2-methyltetrahydrofuran (MTHF) and toluene are presented. The transient absorption study concludes that efficient electron transfer occurs from S2 of zinc meso-tetraphenylporphyrin (ZnTPP) to PI in these porphyrins despite the presence of the intervening phenyl between the zinc porphyrin macrocycle and the PI acceptor.

The parameter estimation of diffusion-mediated fluorescence quenching assuming collisonal quenching to the Smoluchowski-Collins-Kimball (SCK) model is explored. The results indicate that the intrinsic quenching rate coefficient k can be recovered when quenching decays are measured with a sufficiently high number of counts at peak channel and analyzed globally with stationary SV data.

The phase behavior of the novel gemini surfactant, disodium 2,3-didodecyl-1,2,3,4-butanetetracarboxylate (GS), in the presence of water, water/decade, and water/short poly(ox ethylene)nonionic surfactants in a wide range of compositions is described. The GS-water binary system shows a phase behavior typical of ionic surfactant systems, a micellar solution phase and H(sub 1) and R(sub 1) liquid-crystal phases are formed successively with increasing surfactant concentration.

A theoretical model presented to fit the experimental surface pressure/area isotherms of different samples of the surfactant proteins Sp-B and Sp-C is discussed. The basic idea of the model is that the protein molecules at the interface can occupy different areas per molecule depending on the kind of phase, liquid expanded or liquid condensed.

A study is conducted to understand the experimental observation that P(super +) readily quenches the excitation energy from the neighboring accessory bacteriochlorophylls B(sub L) and B(sub M) is presented. It is concluded that the employing transition density formalism for the dimeric doublet transition densities is the key for calculating both the electronic couplings and electronic energy transfer (EET) rate.

The structure and dynamics of the ionic liquid 1-ethyl-3-methylimidazolium nitrate (EMIM-NO3) by molecular dynamics simulations is discussed. The structure of the fluid is characterized by long-range space correlations between the ions and a three-dimensional distribution that reflects the asymmetry of the cations.

Multilayered spherical CdS/HgS nanocrystals consisting of two embedded HgS layers in CdS and multilayered ZnS/CdS nanocrystals with one embedded CdS layer in ZnS are prepared and are characterized by optical spectroscopy, XRD (X-ray diffractometry) and TEM (transmission electron microscopy). The results of the optical spectroscopy are compared to theoretical calculation and TEM results are compared to TEM simulations.

The poly(ethylene oxide) (PEO)-NaSCN SPEs (solid polymer electrolytes) were studied on the basis of the vibrational spectroscopy with differential thermal analysis (DTA) and X-ray diffraction (XRD) measurements and the effect of U/(thiourea) TU content on the ion association and interactions in PEO-NaSCN-U/TU composites is discussed. PEO-NaSCN-thiourea composites possess an amorphous characteristic and can be used to prepare 'salt-in-polymer' electrolytes.

The adsorption behavior and crystallographic structure of copper phthalocyanine (CuPc) on highly oriented pyrolytic graphite (HOPG) at high substrate temperatures is described. Vibrational and structural results suggested that CuPc molecules formed a close-packed structure on the substrate with a face-to-face columnar growth that maintained the lying-flat orientation throughout the growth process.

Using ab initio calculations at the MP2/6-311++g* level, gas phase reactions of silane (SiH4) and diborane (B2H6) were investigated. Under thermal activation, the two molecules could overcome an energy barrier of 33.87 Kcal/mol to associate into a complex SiH4-BH3-BH3 with a hydrogen-bridged Si-H-B bond.

A study was conducted on the perioxidase-oxidase reaction, the influence of nonuniform fields on membrane transport, neuronal systems and calcium signaling. The study discusses the contributions to some fundamental issues in nonlinear science involving the evolution of chaotic behavior through a torus attractor.

The inter- and intra- particle velocities of the perfusive flow field, and intraparticle boundary layer mass transfer are measured. The intraparticle peclet numbers above unity is measured for electroosmatic flow and were found to increase with the applied potential difference.

The microwave spectrum of 2-propenylphosphine (allylphosphine), H2C=CH-CH2-PH2, is analyzed in specific spectral regions at approximately minus forty degrees Celsius. The orientation of the phosphino group is different in the three assigned conformers and a differentiation between the three forms is observed with reference to the lone pair of the phosphino group.

The synthesis and characterization of nanowire-nanoribbon junction arrays of ZnO, which were grown by thermal evaporation of the mixture of ZnO and SnO2 powders at 1300 degree Celsius through a vapor-liquid-solid process is reported. The result indicates that the Sn particles produced by the reduction of SnO2 act as the catalyst.

The qualitative justification for partitioning the energy of the transition structure into contributions from unreactive and reactive moieties are analysed using atoms in molecule (AIM) analysis. The strength and limitations of group additivity (GA) values, as a contribution from the unreactive moiety to express the generic reaction rate in terms of thermochemical contributions of the reactive moiety (subgroup) in the transition structure, is reported along with the effect of varying electronegative and bulky non-next-neighbor substituents.

A method to obtain diffusion coefficients of single-molecule spots in video microscopy images experiments is depicted. The method is based on the size of the single-molecule spot that delivers a maximum number of data points even for short trajectories and a higher statistical accuracy than does the common mean square displacement analysis.

Quantitative description of Methane adsorption on ethylidyne-covered Pt(111) is possible using a kinetic model. This model forces adsorbing molecules through an extrinsic precursor, from which they may desorb or migrate to binding sites on the surface.

A blend of polystyrene and polybutadiene with low-frequency Raman spectra of the block copolymer of polystyrene and polyisoprene is investigated. It is seen that in the diblock, the Boson peaks manifest themselves at frequencies characteristics of pure polymers, so that large regions formed by pure components exist in the diblock.

The results of using alkane lamellae as the molecular buffer layer to immobilize planar molecules, using solutions of binary mixtures of copper phthalocyanine (CuPc) and tetratriaconta (C34H70) as a sample system is presented. The findings showed that copper phthalocyanine molecules formed nanometer-sized domains and adsorbed on top of the alkanine layer.

The wavelength corresponding to the extinction maximum, lambda(sub max), of the localized surface plasmon resonance (LSPR) of silver nanoparticle arrays fabricated by nanosphere lithography (NSL) can be systematically tuned from ~400 nm to 6000 nm. The results demonstrate an unprecedented level of wavelength agility in nanoparticle optical response throughout the visible, near-infrared, and mid-infrared regions of the electromagnetic spectrum.

The formulation and properties of peculiar emulsions of highly concentrated water-in-oil emulsions consisting of five compounds namely, a fluorinated surfactant, a hydrogenated surfactant, a fluorocarbon, a hydrocarbon, and water are prepared and examined. The study of the phase behavior shows that the mixed emulsions are triphasic systems constituted by two kinds of mixed microemulsions coexisting with an aqueous phase.

The isotope exchange technique (IET) was used to measure equilibria and kinetics for adsorption of pure N2, CH4 and Kr on a 4A zeolite sample. The intracrystalline self-diffusive for these gases are measured under truly isothermal conditions. The self-diffusivities of Kr and CH4 are smaller than that of N2 by 2 and 1 order of magnitudes, respectively.

Research into bis(pyrrolidinium) salts has found they are more favourable as building blocks for three-dimensional donor acceptor arrays than bis(carboxylates).

Issues concerning the correlation between configurational order and disorder, molecular sphericity and molecular packing in a series of compounds (CH3)nCCI4-n, which are in phases of plastically crystalline and liquid are discussed.

An investigation into how the milling of a mixture of vanadium supported on titania, in a ball mill, caused the spread of vanadia over the surface of the titania.

Byline: J. Brunvoll (1), S.J. Cyvin (1), B.N. Cyvin (1) Abstract: Treealike octagonal systems (O) are catacondensed systems of octagons, which represent a class of polycyclic conjugated hydrocarbons. Their numbers of isomers are determined and expressed in terms of generating functions. Author Affiliation: (1) Department of Physical Chemistry, Norwegian University of Science and Technology, Na7034, Trondheim, Norway Article History: Registration Date: 23/10/2004

The key step in the formation of CpCr(NO)(PPh3)(CH2SiMe3) from an alkyl-for-iodide metathesis reaction between CpCr(NO)(PPh3)I and Me3SiCH2MgCl involves removal of phosphine ligand. IR and ESR spectroscopic studies help identify four intermediate complexes. Mechanistic studies of this reaction help synthesize 17-valence-electron CpCr(NO)(L)R complexes, where L is a ligand from the chromium coordination sphere.

H2O loss from vapor-absent melting experiments with piston cylinder equipment decreases melt fraction and increases in plagioclase abundance with increase in temperature. In experiments with amphibole gneiss, OH- is the dominant dissolved component in the relatively dry melts. The rate of H2O loss is controlled by the concentration of H2O in hydrous melts, resulting in greater desiccation.

Blue crystals of the infinite bidimensional antiferromagnetic polymer (Ni(N3)2(2,2-dimethylpropane-1,3-diamine))(n) are obtained by the reaction of aqueous solution of Ni(Cl04)2 and NaN3 with 2,2-dimethylpropane-1,3-diamine. The reaction also yields a new coordination mode. The polymer crystallizes when placed in a monoclinic system. Nitrogen atoms in the monoclinic ligand coordinate the Ni(II) atoms octahedrally.

A conformational analysis of the distinct LIM2 metal centers in cysteine-rich protein and cysteine-rich intestinal protein reveals that both protein molecules have a common metal ion coordination pattern. LIM regions in various proteins form similar common conformations. Each protein molecule sequence has a maximum of Zn(II) ions, bound tetrahedrally. Both proteins are largely unfolded in the absence of metal binding.

Analyses directed at preparing and characterizing the first alkoxypolyoxometalates having hydrolytic stability and catalytic oxygenation activity focused on the tris(hydroxymethyl)triesters of (V3P2W15O62)9-, the triester capped polyoxometalates, (RC(CH2O)3V)(super V0 (sub 3) P2W15O59)6- (1-R): (R = CH3, NO2, CH2OH). Significant kinetic stability in relation to hydrolysis is evident for these complexes.

The preparation of a new kind of multifunctional polymer that has a conjugated backbone and a second-order NLO chromophore involved the application of the Stille coupling reaction. A single polymer will exhibit, at the same time, the four functionalities needed to signal the PR effect. The polymers are nonlinear, optically active and photoconductive.

Analyses of decomposition mechanisms of polynitroaromatic compounds involved specific focus on the major thermal processes, particularly in the bulk condensed phase where they start functioning as explosives. Research on thermal decomposition of nitroaromatic explosives is deficient in several areas. Determination of the rates and processes of certain reactions in the bulk compound is very problematic. The conditions that determine the balance between ionic and radical reaction routes in the bulk substance remain obscure.

An improved 3-dimensional form of Huckel molecular orbital theory, derived from the approximations of simple Huckel Theory, with a few more assumptions, chose the right tetrahedral structures from a group of likely polyhedra for the closo-boranes, BnH(sub n)(super 2-). The famous rule of n+1 skeletal electron pairs in closo-boranes is validated.

Different basis sets of varying quality are used in an ab initio SCF theoretical investigation of optimized geometries, atomic populations, electron densities and infrared/electronic spectra of the M2O(sub 7)(super 2-) anions (M = Cr, Mo, W). The extended basis set fails to enhance the results of the MINI-4 basis set, as far as geometrical results are concerned, but is costlier. Central memory usage and disk input/output and pseudopotential basis sets are better than minimal and split-value all-electron basis sets, given a similar investment in computing time.