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A set of new cyclic multiple hydrogen bonded liquid crystals (HBLCs) have been designed and synthesized from citric acid (CA) and 4-dodecyloxybenzoic acid (12OBA). The presence of intermolecular hydrogen bonds (H-bonds) between nonmesogenic and mesogenic compounds has been confirmed by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy and density functional theory (DFT) studies. The hydrogen bonding interactions were explained from natural bond orbital (NBO) analysis using B3LYP/6-311G(d,p) level of theory. Additionally, the Mulliken atomic charges reveal the nature of charge distribution in the HBLC complex. The dynamics of phase transitions and the corresponding stability factor have been evaluated using polarizing optical microscopy (POM), differential scanning calorimetry (DSC), and electrostatic potential (ESP) analysis. Highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies of the CA+12OBA complex is theoretically calculated and experimentally verified. It is found that the variation in the mole ratio in mesogenic with non-mesogenic compound induces the stabilized nematic (N) and smectic X (Sm X) phases. Photocatalytic activity of the CA+12OBA HBLC complex reveals the usage of its optical applications. Key words: HBLC, POM, DFT method, electrostatic potential analysis, photocatalytic activity. Nous concevons et synthetisons un nouvel ensemble de cristaux a multiples liens hydrogeniques cycliques (CLLH/ HBLC) a partir de l'acide citrique (AC/CA) et de l'acide 4-dodecyloxybensoique (120BA). Le lien hydrogene (lien H) intermoleculaire entre composes mesogenes et non mesogenes est confirme par des etudes de transfdormation infrarouge de Fourier (TF-IR/FTIR), de spectroscopie de resonance magnetique nucleaire (RMN/NMR) et de theorie de la fonctionnelle de densite (TFD/FDT). Les interactions de liaison hydrogene s'expliquent a partir d'une analyse d'orbite naturellement liee (ONL/NBO) en utilisant l'approche theorique B3LYP/6-311G(d,p). De plus, les charges atomiques de Mulliken revelent la nature de la distribution de charges dans les cristaux liquides. La dynamique des transitions de phase et le facteur de stabilite correspondant sont evalues par les methodes de microscopie optique polarisee, de calorimetrie differentielle a balayage et d'analyse du potentiel electrostatique (APE/ESP). Nous calculons theoriquement et verifions experimentalement les energies des plus hautes orbites occupees et des plus basses orbites moleculaires non occupees (HOMO-LUMO) du complexe AC-120BA. Nous trouvons que la variation du rapport molaire mesogene avec le compose non mesogene induit les phases stables nematique (N) et smectique X (SmX). L'activite photocatalytique du compose revele ses possibles utilisations optiques. [Traduit par la Redaction] Mots-cles: cristal liquide a liens hydrogeniques (CLLH), methode TFD, analyse du potentiel electrostatique, activite photocatalytique, nematique., Introduction Nowadays, thermotropic liquid crystalline material with theoretical density functional theory (DFT) computation is an innovative technique for studying liquid crystals (LCs). Design and synthesis of LCs from non-mesogenic and [...]

Techniques like emission spectroscopy are used to determine and study the proton, helium and hydrogen temperatures in an extremely large-scale microwave plasma source with a very high microwave power. The study of various temperatures, including the Doppler and rotational temperatures clearly shows that the kinetic temperature of the hydrogen atoms is much higher than the background gas temperature.

The Si:H network was characterized during transformation from amorphous to micro- and nanocrystalline structures aided by increasing [H.sub.2] dilution to the Si[H.sub.4] ensemble in hot-wire chemical vapor deposition (HWCVD). The elevated [H.sub.2] dilution induced enormous polyhydrogenation and formation of lesser sense network full of voids, mostly around the tiny micro/nanocrystallites.

The evolution of in-fiber Bragg gratings' contrast and resonance wavelengths caused by molecular hydrogen loading and subsequent heat treatment in a hydrogen atmosphere at a pressure of 8 MPa is experimentally studied. Changes in the gratings' transmission spectra brought about by room-temperature hydrogen loading followed by isochronal annealing cycles at temperatures up to 700 [degrees]C and at invariable hydrogen pressure are recorded in situ. The gratings' thermal decay dynamics in hydrogen ambience and in air are found to be different and dependent on the gratings' type and on the type of glass in the fiber core. In light of the data obtained, the origin of type IIa gratings is anew under discussion. OCIS codes: 050.2770, 060.2340, 060.2370.

Dielectric properties of Si(111) ultrathin films are investigated using first-principles ground-states calculations in external electrostatic fields. The results show that the dielectric constant is reduced distinctly at the first few bilayers from the surface, which stems from the penetration of depolarized charges induced at the surface.

A different approach is employed to explore plasma propertied by combining an in situ optical emission technique with a contact angle measurement. The plasma excitation and reaction mechanisms for the observed correlation between plasma temperatures and the wettability of the silicon surface is proposed, which shows that small silicon chips can serve as litmus tests for the plasma conditions without introducing too much perturbation.

A new software tool has been developed that provides automated measurement of signal intensities in NMR spectra of complex mixtures without using data reduction procedures. The algorithm finds best-fit transformations between signals in reference compound spectra and the corresponding signals in analyte spectra. Unlike other algorithms, it is insensitive to variation in chemical shift and can even be used for relative quantitation of compounds whose identities have not yet been established. Additionally, the parameters of the transformation provide information and error metrics that may assist in the streamlining of quality control. The approach presented is general in scope but has been tested by application to peak quantitation in NMR spectra of biofluids. Replicate NMR measurements of solutions of biologically important compounds at various concentrations were made. Further NMR data were collected on urine samples from human, rat, and mouse, which were 'spiked' with reference compound solutions at known concentrations. Finally, existing data from an independent toxicology project involving several hundred samples were analyzed, and the consistency of the measurements for metabolites that give multiple NMR signals was assessed. The results of all these tests give confidence that the technique can be used in automated quantitation of compounds in large NMR data sets with minimal operator intervention.

The catalytic process of photoinduced hydrogen generation through the reduction of water is investigated. The use of parallel synthetic techniques has facilitated the synthesis of a 32 member library of heteroleptic iridium complexes that was screened, using high-throughput photophysical techniques, to identify six potential photosensitizers for use in catalytic photoinduced hydrogen production.

The synthesis of the previously unknown 2(7H)-oxepinone and 2(3H)-oxepinone was achieved by elimination of HBr from the reported 5-bromo-6,7-dihydro2(5H)-oxepinone. The gas-phase acidity (detla(sub acid)H(sub 298)) of 2(7H)-oxepinone is determined by means of a bracketing study employing a flowing afterglow apparatus with quadrupole mass spectrometric detection.

A study of the reactivity of H(sub peroxo) is conducted. The findings indicate that the kinetics of single turnover reactions of the two intermediates with ethyl vinyl ether and diethyl ether were monitored by single- and double-mixing stopped-flow optical spectroscopy.

The structure spinosyn G was tentatively identified as 5''-epispinosyn A on the basis of (super 1)H and (super 13)C NMR data, abut the 4'-epi compound could not be ruled out with the data available. If spinosyn G were indeed the 5'-epi compound then the sugar was that of the L-configuration and G represented the only naturally occurring spinosyn with an L-sugar at C-17, in this case, L-ossamine.

N-methyl-2-trialkylsilylmethylpyridinium cations and 4--trialkylsilylmethylpyridinium cations were prepared and investigated using (super 29)Si and (super 13)C NMR and single-crystal X-ray crystallography. Systematic differences in the (super 29)Si chemical shifts and (super 29)Si-(super 13)C one-bond coupling constants for these cations suggested that the Si-CH(super 2) bond interacts more strongly at the 2-position of the electron deficient pyridinium ring than at the 4-position.

N-octadecylcarbamate dodecyl ester is blended individually with a low molecular weight polyethylene and two commercial clarifiers, namely Kemamide S and Kemamide E 180 to understand the role of hydrogen binding in controlling the morphology of self-assembling carbamate systems. The effect of blending on the morphology of this long chain carbamate is investigated using optical microscopy, differential scanning calorimetry, and X-ray diffraction.

The relation between the evolution of photoluminescence (PL) and microstructure of samples is discussed in detail in this paper. The evolution of PL at room temperature from a-Si:H/SiO2 to nc-Si/SiO2 multilayers was observed through step-by-step post treatment.

Essential mechanistic aspects of NO/H2/O2 reaction at 140 degree C were studied using mass spectroscopy and DRIFTS. Inactive adsorb NO(sub x) species (spectators) were found to accumulate on both Pt and support surfaces.

The structure and vibrational spectra for HCO(super -1) , HOCO(super -1), and HCO(sub 2, super -1), calculated at high levels of electronic structure theory are discussed. The changes in the structure of HCO(super -) relative to neutral HCO are consistent with the predictions based on photodetachment experiments.

The structure and vibrational spectra for HCO(super -1) , HOCO(super -1), and HCO(sub 2, super -1), calculated at high levels of electronic structure theory are discussed. There is a very good agreement between the experimental frequencies measured in the solid state for HCO(sub 2, super -1) and the calculated values with the aug-cc-pVD2 basis set.

A comparative analysis of cathodoluminescence spectra is reported. Results indicate that boron is involved in more than one deep acceptor center.

Information regarding the simultaneous photoproduction of hydrogen and oxygen in a confined bioreactor in which the gases accumulate in the headspace above the liquid is presented. An elementary model of gas/liquid interface is developed to calculate the time constant for the movement of oxygen into the gas phase.

Flat-panel displays and solar cells are fabricated with the use of amorphous hydrogenated silicon (a-Si:H). It is found that at higher temperatures, the etching rate decreased due to instability of higher hydrides and completing silicide formation processes.

Hydrogen terminated intrinsic diamond is characterized using photoelectron emission spectroscopy and samples are annealed at temperatures [T.sub.a] from 200 to 1000 degree Celsius. The spectra dominated by photon-phonon interactions are discussed.

Electrical and optical activity of boron incorporated in p-type 4H- SiC layers was observed. Under cathodoluminescence (CL) excitation, efficiency of deep boron related luminescence in compensated material depends on the concentration of attendant impurities (Al, N) and the concentration ratio of AI to N atoms.

Hydrogen production by Anabaena sp. strain 7120 is increased by mutating six nitrogenase amino acid residues predicted to reside within the iron-molybdenum cofactor (FeMo-co) in order to direct electron flow selectively toward proton reduction in the presence of [N.sub.2]. The results have shown the feasibility of engineering cyanobacterial strain for enhanced photobiological production of [H.sub.2] in an aerobic, nitrogen-containing environment.

Photoelectrochemical [H.sub.2] production by solar irradiation has determined the carrier transport properties, reactivity, light absorption strength and has impacted the materialEs efficiency as a photoconverter. The localization or delocalization of the band edges are achieved either due to the orbital nature of the bands or the structural morphology of the material.

The experiments with a Lagmuir probe and optical emission spectroscopy combined with actinometry are carried out in inductively coupled rf Ar/[H.sub.2] discharges in hydrogen fractions. A global model is used for analyzing the effect of Ar dilution to hydrogen discharges on the plasma parameter assuming the Maxwellian electron energy distribution.

The optical beating Brillouin spectroscopy technique is employed to determine the rotational relaxation taking place in the [H.sub.2] (hydrogen) gas. The approach is shown to be extremely useful for a nondestructive analysis of the rotation-translation relaxation of different gases.

The studies of large H atom line broadening observed throughout the volume of surface wave generated He-[H.sub.2] and [H.sub.2] microwave plasmas at low pressures are reported. The measurements obtained for the Doppler temperatures corresponding to the H[beta], H[gamma], H[delta] H[epsi] , and H[zeta] line profiles are found to be higher than the rotational temperature of the hydrogen molecular Fulcher-[alpha] band and the Doppler temperature of the 667.1 nm singlet He line.

The effects of hydrogen microwave plasma treatment on nonhydrogenated high [sp.sup.3] content tetrahedral amorphous carbon (ta-C) film is examined. Thermal stability tests using in situ ultraviolet photoelectron spectroscopy has shown that the C-H dipole has not only reduced the work function of the films, but it is stable in both ambient and vacuum conditions.

Density functional theory calculations are used for studying H complexes in Zn deficient ZnO. The effect of the complexes on the electrical and optical properties of ZnO is examined.

A study is conducted to determine the effect of hydrogen incorporation on the optical properties and crystallization temperature of sputtered Ge[Te.sub.2] films. The crystallization temperature has increased with the addition of hydrogen and a large change in the optical transmission has occured after the phase change from amorphous to crystalline.

The effects of atomic H passivation on the photoluminescence (PL) and microstructure of Si[O.sub.2] films containing Si nanocrystals are examined. The studies have shown that this saturation is consistent with a difference in activation energies for the passivation and depassivation reactions, with the activation energy for the passivation reaction being larger than that for the depassivation reaction.

First-principles calculations combined with semiempirical methods are used for studying the linear electro-optic effect in K[H.sub.2]P[O.sub.4] (KDP). The optical property calculations have shown that the changes in the refractive indices induced by the displacement of hydrogen atoms are related to the flexible degree of the lattice in this semiempirical model.

The laser flash photolysis measurement result for rate constants for 1,5- and 1,6-hydrogen atom transfer reactions in models of polyunsaturated fatty acid radicals that contain aryl groups as surrogates for double bonds is presented. Solvent effects on the rate constants for the 1,5-hydrogen atom transfer reaction of the 2-[2-(diphenylmethyl)-phenyl]ethyl radical at ambient temperature are found to be as large as a factor of 2 with the reaction increasing in rate in lower polarity solvents.

The complete active space self-consistent field (CASSCF) and multiconfiguration second-order perturbation theory (CASPT2) methods were used to study the low-lying electronic states of the [C.sub.2][H.sub.3][Cl.sup.+] ion. The findings from the calculations shed light on the Cl-loss dissociation potential energy curves (PECs) at the CASPT2/CASSCF level.

Blistering of (001) Cz-Si crystals, by either protium (H) or deuterium (D) ions, is analyzed as a function of the sample temperature during implantation. The results are interpreted in terms of models of the interaction of implanted hydrogen with radiation defects and they have shown that dynamic annealing is more efficient in promoting blistering than purely thermal annealing.