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The spectroscopy of an organic molecule adsorbed on the surface of a crystal is studied using the many particle approach. The interaction between electrons and vibrations of the molecule as well as the interaction of crystal electrons between each other and with the electrons of the molecule is taken into account. It is supposed that molecules adsorbed on the surface do not interact one with another directly but rather such interaction arises by the electrons of the crystal. All these interactions give rise to a very complicated dependence of the spectrum. Because all molecules are arbitrarily distributed on the crystal surface the symmetry of the system molecule-crystal surface is small, C1, and so all forbidden rules for absorption and Raman scattering (RS) processes are identical. Numerical simulation of the frequency dependence of absorption (or RS) coefficient, obtained in the framework of micro-approach using the Green function method, showed that at some relations between energy excitation of the molecule and the gap between the electron bands of the crystal film, and also the position of the Fermi level, can result in significant enhancement of absorption (or RS), relative to the free molecule, in the complex molecule-crystal film.

Two molecular complexes of amides (nicotinamide and isonicotinamide) with 3-nitrophenol are characterized by X-ray diffraction and spectroscopic studies. Crystal structure analyses at 100 K revealed different features to distinguish the co-crystals. The asymmetric unit of the crystal structure of nicotinamide–3-nitrophenol (1:1), 1 , consists of two symmetry-independent nicotinamide molecules and two symmetry-independent 3-nitrophenol molecules. The crystal structure of 1 displays an extended hydrogen bond network generated by O H⋯O, N H⋯O and N H⋯N interactions. The structure of isonicotinamide–3-nitrophenol (1:1), 2 , contains O H⋯N hydrogen bonds engaging the pyridine N atom. In 2 , the amide forms a R 2 2 ( 8 ) homodimer which is absent in 1 . The complex 1 shows relatively efficient second harmonic frequency generation.

We studied the influence of Mo and Y substitution in Fe-rich Fe87Zr7B6 on the thermal stability and magnetic properties of thin films obtained from these alloys. The microstructure of the films and its changes were observed by transmission electron microscopy. Coercive field, magnetic induction and effective magnetization, which were determined from measurements of the Kerr effect and ferromagnetic resonance correlated with microstructural transformations.

Fifteen new hydrogen-bonded crystals exhibiting nonlinear optical properties were obtained. For the morpholinium dihydrogenphosphate crystal, the structure was determined by the X-ray diffraction methods. This crystal belongs to the P 2 1 space group of the monoclinic system. The lattice parameters are as follows: a =8.345(2), b =6.156(1), c=9.109(2) A ; β =116.64(3)°. The crystal is built up of the layers parallel to the (001) crystallographic planes. The layer consists of the dihydrogenphosphate chains running parallel to the [010] direction. The morpholinium cation participates in two hydrogen bonds with the O(4) oxygen atoms of dihydrogenphosphate anions belonging to two neighbour chains shifted by the a distance. In such a way, the chains of dihydrogenphosphates are joined by the morpholinium cations into the layer parallel to the (001) crystallographic plane. Additionally, the powder IR and Raman spectra are presented for this crystal.

Thermal stability and magnetic properties of thin films, of a few Fe-based amorphous and nanocrystalline alloys, have been studied. The alloys belong to the class Fe-Μ-Β, whose representatives are: Fe 87 Zr4 Cu1B 8 , Fe87 Zr7 Β6 , and Fe87Zr7Al1Β5 and are of particular interest because of their wide variety of magnetic properties. The films were prepared by flash evaporation onto liquid nitrogen cooled substrates. Measurements of the Kerr effect, the Hall effect, and ferromagnetic resonance in the films were carried out as functions of the annealing temperature. It was found that the changes in the coercive field Ηc , resonance linewidth ΔΗpp, effective magnetization Meff, Hall parameters, and resistance were correlated with the structural changes in the studied films.

The thickness dependence of magnetoresistance was studied for a series of thin Co 20 Ag 80 films. The room temperature magnetoresistance in perpendicular configuration (CIP) was measured for as-deposited and annealed samples in fields up to 2 T. All samples were annealed for 10 min at temperatures ranging from 423 to 623 K at steps of 100 K. MR values growing with the thickness t were observed. MR varies steeply for small t and saturates at larger thicknesses. Changes of the width of the MR curve with the film thickness were also analyzed.

The effects of two food-related chemicals (sodium saccharin and linoleic acid) on the levels of Her2/neu and p53 mRNA in a non-cancerous human breast epithelial cell line (HBL-100) were tested in comparison with the effects of the known tumor promoter phorbol 12-myristate 13-acetate (TPA). Treatments were made both with and without prior treatment with two well-known tumor initiators, N-nitroso-N-methylurea (NMU) or 7,12-dimethylbenz[a]anthracene (DMBA). The effects in general were small, the greatest being increases of 46-67% in Her2/neu mRNA levels in response to treatments with TPA or sodium saccharin following NMU treatments. These results demonstrate that sodium saccharin following NMU treatments might be involved in transcriptional regulation of Her2/neu in HBL-100 cells and suggest that its effects may not be limited to urinary bladder.

The polarized infrared and Raman spectra of a single crystal of betaine phosphoric acid (CH 3 ) 3 N + CH 2 COO − ·H 3 PO 4 were measured. The results obtained are discussed on the basis of the crystal structure. Characteristic spectral features due to hydrogen bond vibrational modes were identified from their polarization behaviour resulting from two short hydrogen bonds connecting the PO 3− 4 groups into infinite chains parallel to the antiferroelectric axis and from two other strong hydrogen bonds linking the betaine molecules and PO 3− 4 groups.

Ab initio calculations have been performed to investigate the molecular structure and vibrational spectra of FF ⋯ NH 3 and FCl ⋯ NH 3 charge transfer complexes. The two dimensional potential energy surface V(r XF , R N t F ) , where X = F, Cl, is obtained by using 6–31G ∗∗ and 6–311G ∗∗ basis sets at the SCF level. The correlation effects are investigated at the MP2 level. The coefficients of the potential energy surface are obtained by an analytical fit to a polynomial expansion up to the fourth or sixth orders. The stretching vibrations deduced from V(r XF , R N t F ) are calculated by means of a variational treatment including a convergence study. It is shown that electron correlation effects must be taken into account to provide reliable stretching vibrations. The results are finally compared with the available experimental data.

Polarized vibrational spectra of a Bet.H3AsO4 single crystal at room temperature (ferroelastic phase) have been measured. The results have been discussed in relation to crystal structure. Absorption due to the antisymmetric stretching vibration (νOH) of the O(4) ⋯ O(4) hydrogen bond which is parallel to the axis of spontaneous polarization has been identified in the infrared spectrum polarized ∥ c axis. The internal vibrations of both the AsO−34 ion and the betaine molecule have been discussed, and assignments of the bands arising from them have been proposed.

Thin Fe-(Cu-Nb)-Si-B films are produced by a flash evaporation method from pulverized Fe 73.5 Cu 1 Nb 3 Si 13.5 B 9 alloy and deposited onto cooled glass substrates. The dependences of the coercive field, H c , and anisotropy field, H K , of the films upon the applied mechanical in-plane uniaxial stress are measured and the magnetoelastic coefficients for H c and H K are determined. Comparing their values with those parameters of thin Ni films assumed as standards, it is possible to determine the isotropic saturation magnetostriction constant, λ s , of the films studied. For as-deposited films λ s = 27 x 10 -6 is found which is a rather reasonable value. This value is, however, considerably reduced after annealing the film at 723 K.

Linear dependence between the experimental Ka line shifts and Mulliken atomic charges obtained by SCF ab initio calculations with 4-31G, 4-31G*, and 4-31G** basis sets for the P, S, and Cl atoms have been found. The electron density redistribution of PCl3 and SPCl3 free ligands on their complexation with AlBr3 has been investigated. It has been shown that a significant transfer of the total ligand electron density to the acceptor is absent, but there is an essential growth of the ionicity of all bonds on complexation. The P = S and PS bond ionicities are found to increase linearly with the growth of the positive charge on the central phosphorus atom. © John Wiley & Sons, Inc.

The structure and energetics of the complexes formed between SO2 and X− (where X = F, Cl, Br, and I) were investigated using an ab initio method at the electron correlation level with effective core potential double-zeta valence basis set with polarization functions. It has been found that the minimum on the potential energy surface corresponds to the pyramidal Cs structure of the complexes whereas the planar C2v structure is the transition state for the inversion process. The stability of the SO2X− complexes fall in the order SO2F− > SO2Cl− > SO2Br− > SO2I− which is in agreement with experimental data.

Evolution of the vibrational spectra of electrochromic thin films WO3·1/3(H2O) during coloration-bleaching process has been studied by Fourier Transform Raman Spectroscopy. It is shown that protons or deuterons inserted into the film during the electrochromic coloration do not play only passive role of charge compensators but strongly distort the film lattice as well. The lattice distortion is reversible during bleaching process up to the charge density of 30 mC/cm2. For the larger coloration density the strong enhancement of Raman effect was observed.

The crystal structure of [(dibenzo-18-crown-6)H 3 O + ](FeCl − 4 ) has been determined by X-ray diffraction and refined to R = 0.06 for 1811 non-zero independent reflections. The oxonium cation is located in the center of the ether cavity. The O(oxonium)⋯O(crown) distances vary from 2.63(1) to 2.73(1) A. Hydrogen bonding interations of the oxonium ion with two O atoms of the crown and with one Cl atom from FeCl − 4 anion are observed.

Thin films of the heavy-fermion system ${\mathrm{UCu}}_{4+\mathit{x}}$${\mathrm{Al}}_{8\mathrm{\ensuremath{-}}\mathit{x}}$ have been prepared and characterized by x-ray diffraction and by microprobe analysis. The films were found to be in an amorphous state and were subsequently investigated by ac-resistivity techniques for frequencies 20\ensuremath{\le}\ensuremath{\nu}\ensuremath{\le}${10}^{9}$ Hz and temperatures 0.1\ensuremath{\le}T\ensuremath{\le}300 K. From these measurements it was concluded that compared to the results in the crystalline bulk material, the onset of magnetic order is suppressed at low Cu concentrations x, while the onset of a coherent heavy-fermion state is suppressed at high x. All samples investigated reveal a single-ion Kondo behavior down to the lowest temperatures. Significant deviations from the behavior of dipolar Kondo systems were detected. Up to the highest frequencies no indications of a narrow Drude peak could be found.

The structure and magnetic properties of thin Fe90–xNixZr10 alloy films with x = 0, 5, and 10 are studied. The structure observed by electron diffraction and transmission electron microscopy reveals the crystalline phase in as-deposited samples. However, the temperature dependence of resistivity suggests the presence of a significant amount of amorphous phase as well. Some new fine-grained structure is observed in the studied films after annealing. Saturation magnetization and magnetization reversal curves are obtained by the Hall effect, and magnetooptical Faraday and Kerr effects, respectively. Ms depends significantly on the alloy composition and weakly on the heat treatment condtions. Hysteresis loops of the films studied reveal very weak uniaxial in-plane anisotropy and undirection-like anisotropy, the latter leading to asymmetric loops shifted along the H-axis. The magnetic properties appear to be consistent with the structure of the studied samples.

Microstructure and magnetic properties of Fe 73.5− x Al x Cu 1 Nb 3 Si 13.5 B 9 ( x =0–9 at% of Al) thin films have been investigated by means of ferromagnetic resonance, coercivity and electrical resistivity measurements. The best soft magnetic characteristics occur for x >5 at% Al due to improvement in microstructure and the effect of substitution of Fe by Al. A linear relation between the coercivity H C and ferromagnetic resonance linewidth Δ H is established.

An attempt is made to crystallize thin amorphous films of Fe73.5Cu1Nb3Si13.5B9 alloy in a nano-crystalline structure. Thin films are prepared by the flash evaporation technique onto glass and rock-salt substrates for electric resistance measurements and for structural studies, respectively. Observations of the changes in resistance on heating of the as-deposited films allow us to investigate the changes in their structure. The electron diffraction and electron microscopic observations show the structural state of the samples as-deposited and after annealing for 10 min at Ta1 = 633 K and Ta2 = 823 K. The results obtained indicate that the nanocrystalline structure can be formed in thin films of the studied alloy during annealing at Ta2, if the as-deposited films were amorphous.

The Hall effect in thin films of Fe80Ti20, Fe85Ti15, and Fe90Ti10 alloys is studied. Unexpectedly, all the samples obtained as vapor-quenched by flash evaporation onto cooled substrates are ferromagnetic at ambient temperature. The spontaneous Hall resistivity, ϱH, decreases with the increase of the iron content. On the contrary, the saturation magnetization, μ0Ms, increases with increasing Fe content. On annealing for 10 min up to about 750 K the above parameters decrease. The correlation of ϱH(T) to the resistivity ϱ(T) suggests the skew scattering to be mainly responsible for the spontaneous Hall effect with some contribution of the side-jump mechanism. Der Hall-Effekt wird in dunnen Schichten der Legierungen Fe80Ti20, Fe85Ti15 und Fe90Ti10 untersucht. Unerwarteterweise sind alle Proben, die durch Flashverdampfen auf gekuhlte. Substrate hergestellt wurden, bei Raumtemperatur ferromagnetisch. Der Hallwiderstand nimmt mit wachsendem Eisengehalt ab, dagegen nimmt die Sattigungsmagnetisierung mit dem Fe-Gehalt zu. Nach Anlassen der Proben fur 10 Min bei 750 K nehmen diese Parameter ab. Die Korrelation des elektrischen Widerstandes und des Hallwiderstandes last Aussagen uber den fur den spontanen Hall-Effekt verantwortlichen Streumechanismus zu.

Proton transfer in the methylnitroamine—trimethylamine complex has been studied by ab initio methods at the SCF and electron correlation (MP2) levels. At the SCF level there is a double well corresponding to the molecular and to the ionic complex. The double well disappears at the electron correlation level and is replaced by a shoulder. If a static electric field, calibrated to correspond to a non-polar solvent, is applied to the complex, the more stable complex is the ionic complex at the SCF level. At the electron correlation level, there is an almost equal probability of finding either the molecular or the ionic form of the complex.

The molecular properties of aminomethylphosphonic acid in the zwitterionic and molecular forms were calculated using the AMI and ab initio methods with the STO-3G ∗ , 3-21G ∗ and 6-31G ∗ basis sets at the self-consistent-field and electron-correlation level. It was found that the molecular form of this acid is 10.4 kcal mol −1 more stable than the zwitterionic one in the gas phase.

Na 2 SeO 4 ·H 2 SeO 3 ·H 2 O crystals are orthorhombic, space group Cmc 2 1 , with α=9.615(6)A, b =11.193(12)A, c =9.615(10)A and Z =4. The crystal structure was determined from three-di- mensional X-ray diffraction data taken on an automatic diffractometer with MoKa radiation and refined by least-squares techniques to R =0.049 for 775 non-zero reflections. The selenate anions and selenious acid molecules occupy C s , sites and form infinite chains through hydrogen bonds with an O⋯O distance of 2.622(15)A. Water molecules of C s symmetry are attached to the selenious acid molecules by weak hydrogen bonds with an O⋯O distance of 2.957(25)A. The second proton (H (61)) of the water molecule interacts with two pairs of oxygen atoms belonging to the neighbouring chains. The stretching vibration of the strong hydrogen bonds (2.622 (15)A) shows a characteristic feature containing two strong bands at ≈ 2800 cm −1 (A) and 2400 cm −1 (B) and a very weak band at ≈ 1500 cm −1 (C), appearing in both IR and Raman spectra. The frequencies of the A and B bands are different in the IR spectra for the X( a ) and Z( c ) polarizations as well as in the polarized Raman spectra. This is due to a strong interaction /coupling between the νOH vibrations of the nearest hydrogen bonds in the same chain. The transition dipole moment of the νOH is almost parallel to the Se(1)⋯Se(2) direction. The δOH vibration gives bands in the region 1300- 1260 cm −1 , while γOH appears at ≈ 790 cm −1 . The internal vibrations of the selenate anions and selenious acid molecules are discussed in terms of a site and factor group effect. An assignment of their bands is proposed in terms of the approximate type of motions using the “oriented gas” model approach. The stretching vibrations of the water molecules appear, in fact, to be stretching vibrations of the hydrogen bonds. It is spectroscopically proved that the H (61) protons of water molecules interact with as many as four ozygens.

Ab initio SCF calculations were performed to investigate the hydrogen-bonding characteristics of the two carbonyl groups of the uracil molecule. The calculated interaction energy of the uracil-HCl complexes shows a strong basis-set dependence and provides no evidence for a significant difference between the two carbonyl groups in terms of intrinsic properties.

This paper presents the first ab initio attempt to construct the stretching fundamentals νFX and νF...N (X=H, D, Li) in the FX...NH3 complexes taking into account the mechanical anharmonicity. A potential‐energy surface V(rFX,RF...N) grid was generated at the self‐consistent‐field and second‐order Mo/ller–Plesset levels. The coefficients fitting the potential‐energy surface up to the fourth order have been used to compute the νFX and νF...N stretching modes. The vibrational problem is solved by means of a variational treatment which includes the effects of mechanical anharmonicity. The results are compared with the available experimental data.

A study of the structure of flash-evaporated Fe-rich thin films of Fe1−xTix (x = 0.10, 0.15, 0.20) alloys deposited onto cooled substrates and its variations on heating are undertaken. Measurements of the temperature dependence of the electrical resistivity and electron microscopic observations are performed. The ϱ(T) curves and the values of ϱ300 and the temperature coefficient of resistivity (TCR) before and after heating suggest that mixed crystalline b.c.c. α-Fe and amorphous FeTi phases coexist within as-deposited films in the composition range (0.08 ≦ x ≦ 0.2). Es wird die Struktur von flashverdampften Fe-reichen Fe1−xTix-Proben mit x = 0,10, 0,15, 0,20, die auf kalten Substraten abgeschieden worden sind, sowie ihre Veranderung wahrend des Temperns untersucht. Dazu werden Messungen der Temperaturabhangigkeit des spezifischen Widerstands und elektronenmikroskopische Untersuchungen durchgefuhrt. Die ϱ(T)-Kurven und die ϱ300-Werte sowie der Temperaturkoeffizient des spezifischen Widerstands vor und nach der Temperung zeigen, das kristalline k.r.z. α-Fe- und amorphe FeTi-Phasen in den abgeschiedenen Schichten innerhalb des Zusammensetzungsbereichs 0,08 ≦ x ≦ 0,2 koexistieren.

The effect of isothermal annealing on the saturation magnetization and Hall resistivity is studied in amorphous evaporated Nd12Co82B6 thin films. Variation in Ms depending on annealing time ta indicates that two relaxation processes occur at a temperature Ta1. A quicker one is probably due to migration of holes and single atoms, and a slower one due to removal of the excess free volume. During further annealing Ms as well as ϱH reveal that the thermally-activated processes remain complex and difficult to analyse. The values of the kinetic exponent n, as determined from the Johnson-Mehl-Avrami equation, seem to confirm the above mentioned suppositions. Der Einflus isothermer Temperung auf die Sattigungsmagnetisierung und den Hallwiderstand wird in dunnen amorphen aufgedampften Nd12Co82B6-Schichten untersucht. Die Anderung von Ms in Abhangigkeit von der Temperungszeit ta zeigt, das zwei Relaxationsprozesse bei einer Temperatur Ta1 auftreten. Ein schnellerer wird wahrscheinlich durch die Migration von Hohlraumen und einzelnen Atomen, ein langsamerer durch die Beseitigung von uberschussigem freien Volumen hervorgerufen. Wahrend weiterer Temperung zeigen sowohl Ms als auch ϱH, das die thermisch-aktivierten Prozesse komplex und schwierig zu analysieren bleiben. Die Werte des kinetischen Exponenten n, wie er aus der Johnson-Mehl-Avrami-Gleichung bestimmt wird, scheinen die obigen Annahmen zu bestatigen.

Adult female B6C3F1 mice received distilled water only or water containing 1.0, 10, or 100 ppb of aldicarb daily for 34 days. The target concentration of aldicarb present in the 100 ppb dosing solution was analytically verified. To further develop an immune profile of this compound, following aldicarb exposure, the ability of splenic natural killer cells and specifically sensitized cytotoxic T-lymphocytes to lyse YAC-1 lymphoma and P815 tumor cells, respectively, was evaluated. To supplement the functional assays, the impact of aldicarb exposure on the percentages and absolute numbers of total T-cells, T-suppressor, T-helper, and B-cells was evaluated. The absence of statistically significant effects on any of these parameters supports earlier reports that aldicarb does not result in adverse effects on the immune system of mice.

Electroluminescent (EL) properties of planar light-emitting nanocomposite structures based on gold island films and semiconducting organic polymers poly(p-pheny!enevinylene) (PPV) and aluminum oxyquinoline (the aluminium (III) 8-hydroxyquinoline complex, Alq3) were studied in 400-600 nm spectral range at room temperature. The chemical composition and structureof vacuum deposited PPV and Alq3 films were determined by IR spectroscopy. According to the obtained data, chemical composition of the deposited A1q3 films corresponds to the initial A1q3. The PPV film is formed of oligomers with smaller molecular weight, which are generated in the course of thermal evaporation in vacuum due to decomposition of initial polymer. It was shown that EL spectra of the nanocomposites consist of two bands, one of them being typical of organic molecules, whereas the second one is related to the luminescence of the island film. Therefore, the obtained planar nanocomposite systems can be used as light emitting structures with controllable electroluminescent properties.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Thin films of Fe-(M-Nb)-Si-B alloys have been prepared by the flash evaporation method. Thermal treatment has been used which should lead to generation of the /spl alpha/-FeSi ultrafine phase. Structural observations showed that the process of film crystallization depends rather on the initial state of the as-deposited films than on the sort of the alloy (M). Either amorphous or crystalline structure was observed in the as-deposited samples which crystallized upon annealing in two different ways. A large amount of the ultrafine phase crystallized in the film which was amorphous when as-deposited and subsequently annealed in optimum conditions. However, a fully homogeneous /spl alpha/-FeSi ultrafine structure throughout the studied films has never been obtained. Magnetic saturation induction and extraordinary Hall coefficient have been determined by Hall effect measurements. >

Infra-red spectroscopy of hydrogen bonded systems is shortly reviewed. Both experimental and theoretical aspects of the problem are covered, but the accent is put on the theory. The first part of the paper refers to the classical, whereas its second part covers the time-resolved spectroscopy of the OH stretching band. Modern theories of vibrational band shapes are presented; they are all based on the density matrix approach of statistical mechanics and employ the correlation function formalism. Using this technique, molecular dynamics of hydrogen bonds can be monitored up to time scales of the order of a few tens of femtoseconds.

Lignin is a widely distributed phenolic biopolymer. Of the three major components of plants — cellulose, lignin, hemicellulose — lignin is, perhaps the least well understood. Its structure and chemical modifications during extraction have been the topic of extensive studies, but yet many questions remain to be answered.

Polarised infrared spectra of single crystals of diglycine hydrochloride (DGC1) have been measured in transmittance andvia external reflection with a microscope. Mathematical treatment of the reflection data by a Kramers-Kronig transformationresulted in very nice spectra, which prove to be similar to the ones measured in transmittance, except for minor differences.The frequencies of the sharp bands are identical but deviations are observed for broad absorptions, and some experience is needed for a proper interpretation of the bands related with hydrogen bonding therefore. The advantages of polarised reflection measurements with a microscope are (i) simplicity of sample preparation (limited crystal growth, no polishing) and(ii) absence of interfering wax absorptions. INTRODUCTION Preparation of a single crystal thin enough for transmittance measurements is a tedious and time-consuming job, whereas reflection measurements by means of an FT-IR microscope can be easily performed on optically selected areas of a

The complex chains of hydrogen bonds of (Beta) -L-arabinose (I), methyl (alpha) -D- glucopyranoside (II) and di-(Beta) -D-fructopyranose 1,2':2,1'-dianhydride (III) in the crystalline state have been studied at variable low temperature. In addition to the increase of information showing up in the overall region upon cooling, the effect on intensity, bandshape and bandmaximum has also been studied. Most surprising is the contradictive behavior of the shift of the band maxima of methyl (alpha) -D-glucopyranoside, for which an increase is observed for the 'free' OH group, while H-bonds absorbing at lower wave-numbers are red shifted. Deuterium exchange experiments show the presence of vibrational coupling in the crystal of II whereas this phenomenon is absent in III.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Variable temperature FT-IR spectra have been recorded of (beta) -D-fructopyranose in the range from 300 to 110 K. The drastic natural resolution enhancement showing up in the OH- stretching region upon cooling yields detailed information with respect to the H-bonded system in the crystalline phase. Based on deuterium exchange experiments we have shown experimentally the presence of vibrational coupling between some of the H-bonded OH groups. Using the spectral information of the noncoupled OH stretching vibrations we have made a tentative assignment in the OH-stretching region.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A review is presented covering the experimental and theoretical aspects of infrared spectroscopy of hydrogen bonded liquids. The discussion is mainly limited to the study of the hydrogen stretching bands perturbed by this interaction. It is shown that their profile is generated by complex relaxation processes in which several oscillators, coupled by anharmonic forces, are simultanously relaxing. These processes are very fast, and the liquid acts, in essence, as a static disordered medium.

We report on the structural and magnetic properties of Co/Ti multilayers in which the soft magnetic state is related to a structural transformation within the crystalline Co sublayers. For all samples with dTi > 1.5 nm, a sudden drop in the coercivity from Hc ≈ 1.4 to ≈ 0.2 kA/m was observed at critical thickness dcritCo ≈ 3 nm. Results show that this transition seems to be evidence of a Co transformation from a polycrystalline to nanocrystalline structure.