Structure of water-in-oil microemulsions of AOT by infrared spectroscopy

Summary The structure of water in water/AOT/n-heptane reverse micelles has been studied as a function of the [H₂O]/[AOT] ratio (W) by using the absorption IR due to O−H stretching modes in the 3800–3000 cm⁻¹ range. The results show that the IR spectra can be expressed as a sum of contributions from bound- and bulk-like water. The fraction of water in the two ?regions? within the water pool was evaluated as a function ofW. The ?bound? water region seems to hold 3.5 water molecules (corresponding to 7 O−H oscillators) per AOT molecule and its formation is nearly complete atW>6. Paper presented at the I International Conference on Scaling Concepts and Complex Fluids, Copanello, Italy, July 4–8, 1994.     

Optical and IR study of Li2O–CuO–P2O5 glasses

Infrared (IR) and UV spectra of ternary Li₂O–CuO–P₂O₅ glasses in two series Li₂O(65−X)%–CuO(X%)–P₂O₅(35%), X = 20, 30, 40 and Li₂O(55−X)%–CuO(X%)–P₂O₅(45%), X = (10, 20, 30) were studied. Infrared (IR) investigations showed the metaphosphate and pyrophosphate structures and with increase of CuO content in metaphosphate glass, the skeleton of metaphosphate chains is gradually broken into short phosphate groups such as pyrophosphate. IR spectra showed one band at about 1,220 and 1,260 cm⁻¹ for P₂O₅(35%) and P₂O₅(45%) series, respectively, assigned to P=O bonds. For CuO additions ≤20 mol%, the glasses exhibit two bands in the frequency range 780–720 cm⁻¹ which are attributed to the presence of two P–O–P bridges in metaphosphate chain. But for CuO addition ≥30 mol%, the glasses exhibit only a single band at 760 cm⁻¹ which is assigned to the P–O–P linkage in pyrophosphate group. In optical investigations, absorption coefficient versus photon energy showed three regions: low energy side, Urbach absorption, and high energy side. In Urbach’s region, absorption coefficient depends exponentially on the photon energy. At high energy region, optical gap was calculated and investigations showed indirect transition in compounds and decreases in optical gap with increases of copper oxides contents that is because of electronic transitions and increasing of nonbridging oxygen content.     

Laser Raman and infra-red spectra of biomolecule: 5-aminouracil

Laser Raman (200–4000 cm⁻¹) and IR (200–4000 cm⁻¹) spectra of 5-aminouracil were recorded in the region 200–4000 cm⁻¹. Assuming a planar geometry and C_s point group symmetry, it has been possible to assign all the 36 (25a′ + 11a″) normal modes of vibration for the first time. The two NH bonds of the NH₂ group appear to be equivalent as the NH₂ stretching frequencies satisfy the empirical relation proposed for the two equivalent NH bonds of the NH₂ group. The two NH₂ stretching frequencies are distinctly separated from the CH/NH ring stretching frequencies. A strong and sharp IR band at 3360 cm⁻¹ could be identified as the anti-symmetric NH₂ mode whereas the band at 3290 cm⁻¹ with smaller density could be identified as the symmetric NH₂ stretching mode. All other bands have also been assigned different fundamentals/overtones/combinations.      

Infrared spectra of S-and R-isomers of biologically active brassinosteroids

Comparative analysis of IR spectra of S-and R-isomers differing in the configuration of OH groups in the side chain of biologically active 24-epi-and 28-homocastasterones and 24-epi-and 28-homobrassinolides is carried out. Stretching vibration frequencies of H-bonded OH groups of isomers of corresponding brassinosteroids practically coincide. The optical density in maxima of these bands is higher in spectra of the R-isomers. Alteration in the configuration of the OH groups weakly influences also the band intensities of CH3, CH₂, and CH groups. Band intensities of stretching vibrations of associated C=O groups of S-and R-isomers also neglibibly differ from each other. Their frequency characteristics do not experience substantial changes. These features differ considerably in IR spectra of castasterones and brassinolides. For castasterones, the difference in frequencies of band maxima of free and bound C=O groups amounts to ∼15 cm⁻¹; for brassinolides, 23 cm⁻¹. Intensities of both bands are approximately equal in spectra of castasterones. The band intensity of free C=O groups of brassinolides is considerably lower than that of H-bonded ones. The above spectral differences can be used to identify these brassinosteroids. Frequencies of both symmetric and antisymmetric deformation vibrations of CH₃ and CH₂ groups are close in spectra of all brassinosteroids studied. The frequency of CH₂ in a CH₂-OC group belongs only to brassinolides; of deformation vibrations of CH in a CH-C=O group, to castasterones. The frequency of stretching vibrations of C-O-C and C-O groups is observed only in spectra of brassinolides. In the region 1130–900 cm⁻¹ of IR spectra of brassinosteroids, stretching vibrations of CC, CCH, and C-OH groups are predominantly observed. In the frequency range 1130–995 cm⁻¹, the optical density of band maxima of S-isomers is higher than that of R-isomers, which can be used to identify isomers. At the same time frequencies of corresponding bands of isomers practically coincide. Differences in the structure of the side chain of brassinosteroids do not influence essentially the frequency characteristics of the IR spectra. The exception is the band related to stretching vibrations ν(C23-OH) of the side chain which features a considerable frequency ν_max ≈ 983 cm⁻¹ only in spectra of R-isomers of homocastasterone and brassinolide. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 5, pp. 623–630, September–October, 2008.     

Vibrational spectra of Na4P2O7·10H2O

The IR and Raman spectra are measured and analysed for sodium pyrophosphate decahydrate. The spectra are interpreted on the basis of P₂O ₇ ⁴⁻ ion and water vibrations. The observed results fit with the features predicted for the factor goup model. The appearance of two sets of frequencies in the stretching and bending regions of water suggests the existence of two kinds of water molecules in the crystal. This is confirmed by deuterium substitution.     

IR spectroscopic manifestations of hydration of poly(diphenyl sulfophthalide) during its storage

IR spectroscopy measurements show that films of poly(diphenyl sulfophthalide) (PDSP), a cardo polymer, interact with atmospheric moisture during storage at room conditions. A total of 15 absorption bands were isolated in spectra of PDSP hydrated during storage, which belong to sorbed water and hydrolysis products. A number of absorption bands (within 1500–1800 cm⁻¹ and 980–1100 cm⁻¹) were obtained by subtracting the spectrum of the film after heating from that of the initial hydrated film. At least six individual bands in the region of the O-H bond stretching vibration were isolated by decomposing a broad complex band (3700–2000 cm⁻¹) into Gaussian components. The isolated bands were tentatively assigned based on the available literature data and quantum-chemical calculations of the characteristics of a number of complexes of a diphenyl sulfophthalide model compound with water molecules. The IR spectra and energies of the hydrogen bonds formed were calculated at the B3LYP/6-311G(d, p) level. In particular, the absorption bands at 1010 and 1079 cm⁻¹ were assigned to the symmetric stretching vibrations of the S=O bonds in the −SO₃⁻ anion, the 1062-cm⁻¹ absorption band, to ν(C-OH), and the absorption bands at 3646, 3586, and 3475 cm⁻¹, to complexes of water with sulfophthalide cycles of the polymer. After a long storage, PDSP largely transforms into a polymeric oxonium salt, and its spectrum becomes similar to that of a polymeric salt prepared by alkaline hydrolysis. A general mechanism of the interaction of PDSP with water is proposed, according to which the hydrolysis of the sulfophthalide cycles (SPC) by sorbed water yields new hydrophilic groups, sulfoacid, and hydroxyl groups. A further sorption of water by the sulfoacid results in its ionization and the formation of various hydroxonium forms. Sorption and hydrolysis are reversible processes: water is desorbed and the SPC is recovered when the polymer is heated to 100–150°C, as can be judged from an increase in the intensity of the S=O bond vibrations of the sulfophthalide cycle at 1352 and 1192 cm⁻¹. The possibility of using strongly hydrated PDSP for manufacturing proton-conducting membranes is discussed.     

Infrared spectra of BeSO4.4H2O and its deuterated analogue in 4000–1200 cm−1 region

IR spectra of BeSO₄.4H₂O and its deuterated analogue at ∼300 K and ∼110 K are reported in the region 4000–1200 cm⁻¹ using thin film and nujol mull techniques. The observed bands have been assigned as the internal modes of the water and the overtones and combinations of various modes using the recently revised assignments of SO₄ ²⁻ and Be(aq)₄ fundamentals in the region 1200–250 cm⁻¹ (Srivastavaet al 1976). The splitting of the internal modes of water has been discussed in the light of the effects of deuteration and cooling and it is shown that all the water molecules in a unit cell are asymmetric but crystallographically equivalent.     

Conversion of ortho-para H2O isomers in water and a jump in erythrocyte fluidity through a microcapillary at a temperature of 36.6±0.3°C

A mechanism is proposed for the previously observed [1] jump in erythrocyte fluidity through a microcapillary 1.3 μm in diameter at a temperature of 36.6±0.3°C. Our interpretation is based on the experimental evidence both for existence of ortho and para H₂O isomers in water and on spin-selective interaction of proteins with para H₂O isomers as hydration shells of biomolecules are being formed [2]. It is important that the formation of hydration shells of proteins and DNA in aqueous solutions is accompanied by an increase in the Brillouin shift to 0.4 cm⁻1 (≃0.25 cm⁻¹ in water), which points to the formation of icelike structures. We believe that the coincidence of the translational energy kT of the Brownian motion and the energy of the rotational quanta for the 3₁₃–2₀₂ transition of para H₂O isomers at the temperature 36.6°C increases the probability for excitation of para H₂O isomers in collisions. Collisions mix quantum states of closely spaced levels in para H₂O (3₁₃, 285.2 cm⁻¹) and ortho H₂O (3₃₀, 285.4 cm⁻¹) and induce conversion of para isomers to ortho H₂O. It is assumed that this conversion in the icelike hydration shell of hemoglobin (Hb) is accelerated under the catalyzing effect of oxygen and iron present in Hb and triggers a chain reaction: release of ortho H₂O isomers through the erythrocyte membrane→compaction of Hb molecules and increase in concentration of catalysts→acceleration of conversion→structural gel-sol transition. It is the sequence of these processes that provides a jump in fluidity of erythrocytes through a microcapillary and the anomalous increase in fluidity of the aqueous solution of hemoglobin by almost an order of magnitude at temperatures close to 36.6°C and an increase in the solution concentration by a factor of 1.7.     

Structure of zinc-borate low-melting glasses derived from IR spectroscopy data

The IR spectra of glasses of the ZnO—SrO—B₂O₃ system with constant additions of PbO, Al₂O₃, and Li₂O (20 mol. % in sum) were studied. It is established that on replacement of B₂O₃ by ZnO, the structure of the glasses is characterized by the presence of groupings with the bridge bonds B^III— O—B^III, B^III—O—B^IV, B^IV—O—B^IV and end groups B^III— O⁻; ZnO practically exerts no influence on the coordination transition [BO₃] → [BO₄]. At a high content of ZnO, zinc ions are present in both a six-and a four-coordinated state. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 6, pp. 778–781, November–December, 2005.     

Synthesis and characterization of novel nano-size polyreactive yellow 107

The reactive yellow 107 was polymerized by chemical oxidation method using potassium persulfate. The polymer was characterized by UV-VIS and Fourier transform infrared spectroscopy (FTIR) spectral studies. The peaks at 2,922 and 2,852 cm⁻¹ in the FTIR spectrum of polyreactive yellow 107 are assigned to the symmetric and asymmetric stretching vibrations of CH₂. The peak observed at 1,583 cm⁻¹ for polyreactive yellow 107 may be assigned to the stretching vibration of C=O, N=N, and C=C, 1,347 cm⁻¹ stretching vibration of C–N. The stretching vibrations of sulfone and sulfonic acid of S=O groups show a strong broad peak at 1,091 and 1,051 cm⁻¹. The conductivity of the polymer was determined to be 5.57 × 10⁻⁵ S cm⁻¹. The solubility of the chemically polymerized powder was ascertained and polyreactive yellow 107 showed good solubility in N,N-dimethyl formamide and dimethyl sulfoxide. The X-ray diffraction studies revealed the formation of nano-sized (84 nm) crystalline polymer. Using X-ray diffraction, behavior strain and dislocation density was also calculated. Scanning electron microscope analysis showed uniform crystalline nature of the polymer (200 nm). The thermogravimetric analysis, differential thermal analysis, and differential scanning calorimetry studies revealed good thermal stability of the polymer.     

Infrared spectra of brassinolide and castasterone steroid phytohormones and their 24-epi derivatives

Absorption bands in IR spectra of brassinolide, castasterone, and their 24-epi derivatives in the frequency range 3800–1000 cm^–1 have been interpreted. A number of spectral features distinguishing brassinolide from castasterone have been found. The conducted analysis shows that the structural differences manifest themselves in IR spectra of the investigated brassinosteroids in the region of stretching vibrations of CO–H, C=O, C–OH, C–O–C, CH₃, CH₂, and CH groups. The main distinctions in IR spectra of brassinolides and castasterones are due to the B ring structure.     

Four-wave mixing spectroscopy of aqueous suspensions of single-wall carbon nanotubes in the ranges of 0.1–10 and 100–250 cm<Superscript>−1</Superscript>

Distinctive optical properties of single-wall carbon nanotubes (SWNT) are highly sensitive to variations in the environment. Here, we have studied SWNT in aqueous suspensions at a low (less than 0.1 μg ml⁻¹) concentration by four-wave mixing (FWM) spectroscopy in the spectral bands of 0.1 to 10 cm⁻¹ (≈300 GHz) and 100 to 250 cm⁻¹ (3 to 7.5 THz). We directly investigated the hydration layers around SWNT. A comparison of the FWM spectra of an SWNT aqueous suspension and Milli-Q water shows a considerable increase in the intensity of low-frequency Raman modes, which are attributed to the rotational transitions of H₂O₂ and H₂O molecules. We explain the observed phenomenon by the hydrogen peroxide production and formation of a low-density depletion layer at the water-nanotube interface. We have observed several SWNT radial breathing modes ω _RBM =118.5, 164.7, and 233.5 cm⁻¹ in an SWNT aqueous suspension and estimated the corresponding SWNT diameters as ≈2.0, 1.5, and 1 nm.     

Spreading of an SR beam spot (diameter 0.5 μm, 95 eV) photoelectron image on the surface of WO<Subscript>3 − <Emphasis Type="Italic">x</Emphasis></Subscript> films

The 2D-photoemission image of the beam spot was obtained for the first time for the W⁵⁺ oxidation state on the preliminary irradiated WO_{3 − x} thin film surface, created by scanning of the SR beam over the film surface. The W⁵⁺ beam profile intensity was found to spread up to a distance of 3.2 μm for an amorphous film and 5.5 μm for a polycrystalline film, it exceeds considerably the beam spot size. The image saturation dose was reached faster for a polycrystalline film. Among the possible mechanisms explaining this phenomenon, for the case of an almost unchangeable O2s state under irradiation, a choice was made in favor of a photon-generated charge diffusion due to low-energy secondary electrons from photoemission, which produce the “coloration” effect, e⁻ + W⁶⁺ (W⁵⁺) W⁵⁺ → W⁵⁺(W⁴⁺). The O512-eV Auger peak was found to degrade at the distance of 1.5–2 mm outside the beam spot under long-time electron beam irradiation, which is attributed to electron-stimulated oxygen desorption and outdiffusion.     

Ion transport studies in zinc/cadmium halide doped silver phosphate glasses

A number of samples of silver phosphate glasses Ag₂O−P₂O₅−Zn/CdX₂ (X=Cl, Br or I) with 1, 5, 10 and 20 mol-% zinc or cadmium halides have been prepared. Control samples of undoped silver phosphate glasses were also prepared. These glasses were characterized by elemental analysis, X-ray diffraction, IR spectra, differential scanning calorimetry, transference number measurements and electrical conductivity studies. These glasses were found to be essentially ionic conductors. The undoped silver phosphate glass (Ag₂O−P₂O₅) has a low σ value in comparison to the doped ones. The conductivity (σ) in the doped glasses increases substantially with increasing concentration of dopant salts Zn/or CdX₂ and as the anions of the dopants are changed from Cl⁻ to I⁻. It is found that the σ values of the ZnX₂ doped glasses are slightly greater than those of the CdX₂ doped ones, and the silver phosphate glasses doped with (20 mol-%) Zn/CdI₂ yielded maximum conductivity. The results have been discussed and explained on the basis of changes in the structure of the glass matrix by the addition of dopant ions of different sizes, IR spectra and thermal studies.     

Ion-molecular interactions in the methylsulfonic acid—methanol system according to the IR spectral data

The methylsulfonic acid (MSA)—methanol (MeOH) liquid binary system was studied over the whole concentration range by the MBTIR IR spectroscopy method at 30°C. Quasi-ion pairs with the 1: 1 composition formed by a strong symmetrical H-bond were only present in solutions with an equimolar acid: base ratio. The addition of methanol caused the solvation of quasi-ion pairs by MeOH molecules, and, in the presence of the base in a substantial excess (C _MeOH⁰: C _MSA⁰ > 2), proton disolvates (Me(H)O⋯H⋯O(H)Me)⁺ with strong symmetrical H-bonds were formed; that is, there was B⋯H⋯A + B ↔ (B⋯H⋯B)⁺ + A⁻ equilibrium, where B is the base molecule and HA is the acid. In the presence of excess acid, methanol was protonated, and negatively charged proton disolvates were formed, B⋯H⋯A + HA ↔ BH⁺ + (AHA)⁻. This equilibrium was fully shifted to the right.     

Excess thermodynamic quantities of D<Subscript>2</Subscript>O water calculated from its Raman O−D stretching spectra

Excess thermodynamic functions of D₂O water have been calculated from the vibrationally decoupled O−D stretching spectra of very dilute solutions of HOD in H₂O. Comparison of the results with reference calorimetric data for water showed a good correspondence for excess heat capacity above the melting point of ice. The excess enthalpy at the melting point also coincides well with latent heat of melting.     

Determination of the degree of crystallinity of poly(vinyl alcohol) by FTIR spectroscopy

Quantitative correlations between the intensity of the crystalline band at 1144 cm⁻¹ (A ₁₁₄₄) normalized to the intensity of the C–O stretching band at 1094 cm⁻¹ (A ₁₀₉₄) in IR spectra of PVA films and the degree of crystallinity (α) of these films measured by an x-ray diffraction method were investigated. It was found that α and A ₁₁₄₄/A ₁₀₉₄ were related by the linear dependence α (%) = a + b(A ₁₁₄₄/A ₁₀₉₄) with correlation coefficient 0.999 for α values in the range 18–60%.     

Optical and IR studies on r.f. magnetron sputtered ultra-thin MoO3 films

Ultra-thin MoO₃ films were deposited onto glass and Si substrates by r.f. magnetron sputtering. The optical and IR properties of the films were studied in the range of 250 to 1000 nm and 400 to 1500 cm⁻¹, respectively. The optical transmission spectra show a significant shift in absorption edge. The energy gap of the films deposited at 373 K and 0.1 mbar was found to be 3.93 eV, and it decreases with increasing substrate temperature and decreasing sputtering pressure. The IR transmittance spectra shows strong modes of vibrations of Mo=O and Mo–O–Mo units of MoO₃ molecule. A significant change in energy gap and a shift in frequency of IR modes were observed in ultra-thin MoO₃ films.     

Signatures of anomalous couplings in boson pair production throughγγ collisions

We discuss possible New Physics (NP) effects on the processesγγ →W ⁺ W ⁻,ZZ, Zγ, γγ, HH which are observable inγγ collisions. Such collisions may be achieved through laser backscattering at a high energye ⁺ e ⁻ linear collider. To the extent that no new particles will be directly produced in the future colliders, it has already been emphasized that the new physics possibly hidden in the bosonic interactions, may be represented by the sevendim=6 operatorsO _W,O _BΦ,O _WΦ,O _UB,O _UW and (the last two ones being CP-violating). In this paper, we show that the above processes are sensitive to NP scales at the several TeV range, and we subsequently discuss the possibility to disentangle the effects of the various operators. Partially supported by the EC contract CHRX-CT94-0579     

Spectral characteristics of water clusters in the interaction with ozone molecules and bromide ions

The molecular dynamics method is used to study the interaction of the (Br⁻) _i (H₂O)_{50 − i} clusters in a medium of water vapor with ozone molecules. The clusters absorb O₃ molecules and retain them, along with Br⁻ ions, for a 25-ps-long calculation procedure. The presence of bromide ions results in significant increases in the values of the real and imaginary parts of the relative permittivity. The addition of bromide ions causes a significant increase in the integrated IR radiation absorption intensities and in the radiant power emitted by the clusters. The addition of Br⁻ ions only slightly affects the intensity of the Raman spectra until the number of Br⁻ reaches six, when a dramatic decrease of the integrated intensity of this spectrum occurs. Bromide ions absorbed by water clusters produce a much more lasting impact on the ozone molecules trapped by the cluster than chlorine ions do, all other things being equal.