FTIR spectra of plasticized high molecular weight PVC–LiCF3SO3 electrolytes

Fourier transform infrared spectroscopy studies have been conducted to investigate the interaction among components in a system of high molecular weight polyvinylchloride (PVC)–lithium trifluoromethanesulfonate (LiCF₃SO₃) incorporated with different type of plasticizers, namely, ethylene carbonate (EC), propylene carbonate (PC), and dibutylphthalate (DBP). Interaction between PVC and LiCF₃SO₃ was confirmed by C–H rocking mode at 1,255 cm⁻¹ for PVC shift to 1,252 cm⁻¹ in PVC–LiCF₃SO₃. The plasticizers’ carbonyl (C=O) oxygen atom which carries lone pair electrons interact with Li⁺ of LiCF₃SO₃ and methine hydrogen of PVC in LiCF₃SO₃–plasticizer system and PVC–plasticizer system, respectively. Changes in peaks assigned to 1,264 cm⁻¹ (ν _as(SO₃)), 1,033 cm⁻¹ (ν _s(SO₃)), 1,181 cm⁻¹ (ν _as(CF₃)), 1,230 cm⁻¹ (ν _s(CF₃)), 765 cm⁻¹ (δ _s(CF₃)), 644 cm⁻¹ (δ _s(SO₃)), 578 cm⁻¹ (δ _as(CF₃)), and 519 cm⁻¹ (δ _as(SO₃)) indicate the occurrence of complexation in the PVC–LiCF₃SO₃ system, LiCF₃SO₃–plasticizer system, and PVC–LiCF₃SO₃–plasticizer system.     

Grafted natural rubber-based polymer electrolytes: ATR-FTIR and conductivity studies

Attenuated total reflectance–Fourier transformed infrared spectroscopy measurement is employed to study the interactions between the components of 30% methyl-grafted natural rubber (MG30), lithium trifluromethanesulfonate (LiCF₃SO₃ or LiTF), and propylene carbonate (PC). Vibrational spectra data of LiTF reveals that the ν_s(SO₃) at 1,045 cm⁻¹, δ_s(CF₃) at 777 cm⁻¹, and C=O stretching mode at 1,728 cm⁻¹ for MG30 have shifted to lower wave numbers in MG30–LiTF complexes indicating that complexation has occurred between MG30 and LiTF. The solvation of lithium ion is manifested in Li⁺ ← O=C interaction as shown by the downshifting and upshifting of C=O mode at 1,788 to 1,775 cm⁻¹ and ν_as(SO₃) at 1,250 to 1258 cm⁻¹, respectively, in LiTF–PC electrolytes. There is no experimental evidence of the interaction between MG30 and PC. Competition between MG30 and PC on associating with lithium ion is studied, and the studies show that the interaction between MG30–LiTF is stronger than that of the PC–LiTF in plasticized polymer–salt complexes. The effect of PC on the ionic conductivity of the MG30–LiTF system is explained in terms of the polymer, plasticizer, and salt interactions. The temperature dependence of conductivity of the polymer films obeys the Vogel–Tamman–Fulcher relation. Values of conductivity and activation energy of the MG30-based polymer electrolyte systems are presented and discussed.     

Observation of simultaneous ν1(SF6) + ν3(NF3) and ν2(SF6) + ν3(NF3) transitions enhanced by the resonance dipole-dipole interaction with the ν1 + ν3 and ν2 + ν3 states of the SF6 molecule

IR spectra of the solution of SF₆ molecules in liquid NF₃ at 84 K have been recorded. In a solvent transmission window of 1500–1750 cm⁻¹, two wide absorption bands with pronounced peaks in the high-frequency part are observed. The profile of these bands is explained by the influence of the resonance dipole-dipole (RDD) interaction of the states of the simultaneous transition ν₁(SF₆) + ν₃(NF₃) and ν₂(SF₆) + ν₃(NF₃) with the states (ν₁ + ν₃) and (ν₂ + ν₃) of the SF₆ molecules, respectively. The use of three isotopic modifications ³²SF₆, ³³SF₆, and ³⁴SF₆ has allowed us to vary the resonance detuning and thus to change the strength of the RDD interaction. With the liquid near the melting point being represented as a close-packed cubic crystal, the profile was calculated and its spectral characteristics were determined. The frequencies of the main peaks coincide with the experimental values accurate to the error.     

Electron-vibrational energy exchange in collisions of Ar atoms in the 3P2 metastable state with N2(X1S g+ ) molecules

Rate constants for electron-vibrational energy exchange Ar(³ P ₂) + N₂(X ¹Σ _g ⁺, ν = 0) → Ar(¹ S ₀) + N₂(C ³Π _u , ν′), where ν′ = 0, 1, 2, were calculated. Calculations were performed taking into account the presence of a resonance in electron scattering by N₂(X ¹Σ _g ⁺). As a result, the interaction of Ar(³ P ₂) with N₂(X ¹Σ _g ⁺, ν = 0) was characterized by attraction and, in the end, intersection of electron-vibrational potential surfaces correlating with Ar(³ P ₂) + N₂(X ¹Σ _g ⁺, ν = 0) and Ar(¹ S ₀) + N₂(C ³Π _u , ν′) at interparticle distances of 2.5–3.5 ?. Exchange interaction at which electron-vibrational transitions in the region of intersection of electron-vibrational transitions in the region of intersection of electron-vibrational potential surfaces accompanied by spin exchange were induced was calculated by the asymptotic method. The rate constants determined at 300–600 K were on the order of 10⁻¹¹−10⁻¹² cm³/s and weakly increased as the temperature grew. Mainly the C ³Π _u , ν′ = 0 state of the N₂ molecule was populated. The calculation results were in satisfactory agreement with the experimental data obtained at 300 K.     

Intermolecular hydrogen bonds in acetic acid and its solutions

The band at 896 cm⁻¹ in the Raman spectrum of acetic acid consists of at least two lines (873 and 896 cm⁻¹) whose intensities and depolarization factors differ strongly. A temperature increase leads to an increase in the intensity of the 873-cm⁻¹ line as compared to the intensity of the 896-cm⁻¹ line. Dilution of the acid with acetonitrile leads to a similar but much more pronounced effect. In solutions with CCl₄ and water, the relative intensity of the low-frequency line decreases; in aqueous solutions, the width of the 896-cm⁻¹ line passes through a maximum with 0.4 mol. fractions of the acid (for this concentration, the line width is larger by a factor of 2.5 than in a pure liquid), while in the solutions with CCl₄ it decreases smoothly (almost twofold with strong dilution: 0.05 mol. fractions). Experimental data are in agreement with the assumption that the 873- and 896-cm⁻¹ lines refer to the vibrations of the same atoms in a molecule and to associates with a free and an H-bonded atom of the oxygen of a C=O group, respectively. The difference in the frequencies and depolarization factors of the lines causes the differences in the distribution of an electron cloud in the molecule. To whom correspondence should be addressed. Alisher Navoi Samarkand State University, 15, Universitetskaya Str., Samarkand, 703004, Uzbekistan. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 4, pp. 467–470, July–August, 1999.     

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.     

Recoil distance half-life measurements of the excited states in 145Sm

A recoil distance method was used to measure half-lives of the excited states of ₁₄₅Sm. The reaction used was ₁₃₉La(₁₀B, 4n)₁₄₅Sm. A plunger system was used. Half-lives were determined for two excited states for the first time. The yrast 27/2₊ state was found to have a half-life of 1.1 ± 0.2 ns corresponding to the retardation of 3.1 × 10₋₄ comparing with the single particle estimate of M1. The excitation energy of this state was well reproduced by the shell model calculation having a mixed configuration of [π{h^11/2(g^7/2)₋₂ (d^5/2)₋₁}¹⁰⁻, νf^7/2] + [π{h^11/2(g^7/2)₋₁}⁹⁻,νh^9/2]. Another retarded E1 transition was also found in a decay of a 21/2₊ state. Its retardation was 1.6 × 10₋₄ comparing with the single particle value. Received: 9 September 1997 / Revised version: 12 June 1998     

Effect of plasmon-phonon excitations on the coefficient of reflection from the surface of hexagonal silicon carbide

The coefficient R(ν) of reflection from the surface of 6H-SiC single crystals is studied in the case in which the long-wavelength optical vibrations of the lattice are coupled with the electron plasma. It is shown for the first time that the anisotropy of the properties of electrons and phonons in 6H-SiC gives rise to special features in the spectrum of the coupled vibrations and the transparency regions. It is found, in particular, that if the axis of the crystal lies in the polarization plane of the incident radiation (0<θ<90°), for 30 cm⁻¹⩽ν _p⊥<320 cm⁻¹ the spectrum of R(ν) acquires three regions of transparency and opacity, and for ν _p⊥⩾320 cm⁻¹ four such regions, which are absent in an isotropic medium. The width of these regions is found to depend on the electron concentration in the conduction band and on the angle θ. Zh. éksp. Teor. Fiz. 116, 646–654 (August 1999)     

The rate constants of singlet oxygen collision-induced emission at 634 and 703 nm wavelengths

Absolute spectral luminosity from an O₂–O₂(a)-H₂O gas flow formed by a chemical singlet oxygen generator was measured at 600–800 and 1230–1310 nm wavelengths. The results were used to determine the rate constants for O₂(a, 0) + O₂(a, 0) → O₂(X, 0) + O₂(X, 0) + hν (λ = 634 nm) and O₂(a, 0) + O₂(a, 0) → O₂(X, 1) + O₂(X, 0) + hν (λ = 703 nm) collision-induced emission ((6.72 ± 0.8) × 10⁻²³ and (7.17 ± 0.8) × 10⁻²³ cm³/s, respectively).     

Universal magnetoluminescence kinetics in magnetically frozen 2D electron systems

The kinetics of recombination of electrons and acceptor-bound holes in AlGaAs-GaAs heterostructure obey a single-exponential decay in the liquid phase of 2D electrons, whereas localization gives rise to a broad spectrum of recombination rates, especially in the magnetic freeze-out regime. This results in a power-law dependence I(t)∝(τ/t)^α in the tail of the recombination kinetics, with the universal exponent α=(1−ν)⁻¹ at ν<1 for all the samples examined experimentally in this work. Pis’ma Zh. éksp. Teor. Fiz. 63, No. 2, 118–122 (25 January 1996) Published in English in the original Russian journal. Edited by Steve Torstveit.     

Reversibility of Some Chordal SLE(<Emphasis Type="Italic">κ</Emphasis>;<Emphasis Type="Italic">ρ</Emphasis>) Traces

We prove that, for κ∈(0,4) and ρ≥(κ−4)/2, the chordal SLE(κ;ρ) trace started from (0;0⁺) or (0;0⁻) satisfies the reversibility property. And we obtain the equation for the reversal of the chordal SLE(κ;ρ) trace started from (0;b ₀), where b ₀>0.     

The temperature dependence of the spectral width of singlet oxygen dimole emission

In the temperature range of T = 150–400 K, the dependence of spectral widths (cm⁻¹) on temperature, 182 + 0.38(±0.01)T and 217 + 0.48(±0.01)T, respectively, has been obtained for dimole emission of O₂(a, 0) + O₂(a, 0) → O₂(X, 1) + O₂(X, 0) + hν (λ = 703 nm) and O₂(a, 0) + O₂(a, 0) → O₂(X, 0) + O₂(X, 0) + hν (λ = 634 nm). It was shown that the ratio of dimole emission rate constants does not depend on temperature in the range of 150–400 K and is 1.06 ± 0.01.     

The Baikal Neutrino Experiment: Status and beyond

The present status of the Baikal Neutrino Experiment and the present results of a search for upward going atmospheric neutrinos, WIMPs, and magnetic monopoles obtained with the NT-200 detector are reviewed. The results of a search for very high-energy neutrinos are presented as well. An upper limit on the ν _e +ν _e +ν _τ neutrino diffuse flux of E ²Φ(E)<1.3×10⁻⁶ cm⁻² s⁻¹ sr⁻¹ GeV within a neutrino energy range of 10⁴–10⁷ GeV is obtained, assumingan E ⁻² behavior of the neutrino spectrum and a flavor ratio ν _e :ν _π :ν _τ =1:1:1. We also describe the moderate upgrade of the NT-200 planned for the next few years and present a possible detector on the Gigaton scale. From Yadernaya Fizika, Vol. 67, No. 6, 2004, pp. 1186–1194. Original English Text Copyright ? 2004 by Aynutdinov, Balkanov, Belolaptikov, Bezrukov, Budnev, Chensky, Chernov, Danilchenko, Dzhilkibaev, Domogatsky, Dyachok, Gaponenko, O. Gress, T. Gress, Klabukov, Klimov, Klimushin, Konischev, Koshechkin, Kulepov, Kuzmichev, Kuznetzov, Lubsandorzhiev, Mikheyev, Milenin, Mirgazov, Moiseiko, Osipova, Panfilov, G. Pan'kov, L. Pan'kov, Parfenov, Pavlov, Pliskovsky, Pokhil, Polecshuk, Popova, Prosin, Rosanov, Rubtzov, Semeney, Shaibonov, Spiering, Streicher, Tarashansky, Vasiliev, Vyatchin, Wischnewski, Yashin, Zhukov. This article was submitted by the authors in English.     

On Minimal Eigenvalues¶of Schrödinger Operators on Manifolds

We consider the problem of minimizing the eigenvalues of the Schr?dinger operator H=−Δ+αF(κ) (α>0) on a compact n-manifold subject to the restriction that κ has a given fixed average κ₀. In the one-dimensional case our results imply in particular that for F(κ)=κ² the constant potential fails to minimize the principal eigenvalue for α>α_c=μ₁/(4κ₀ ²), where μ₁ is the first nonzero eigenvalue of −Δ. This complements a result by Exner, Harrell and Loss, showing that the critical value where the constant potential stops being a minimizer for a class of Schr?dinger operators penalized by curvature is given by α _c . Furthermore, we show that the value of μ₁/4 remains the infimum for all α >α _c . Using these results, we obtain a sharp lower bound for the principal eigenvalue for a general potential. In higher dimensions we prove a (weak) local version of these results for a general class of potentials F(κ), and then show that globally the infimum for the first and also for higher eigenvalues is actually given by the corresponding eigenvalues of the Laplace–Beltrami operator and is never attained. Received: 17 July 2000 / Accepted: 11 October 2000     

The electric quadrupole interaction of 111Cd in ZrZn2 and Zn in the samples prepared at 8 GPa

The perturbed angular correlation (PAC) measurements with the ¹¹¹In-¹¹¹Cd nuclear probe embedded into the lattice of the cubic (C15) Laves compound ZrZn₂ showed that ¹¹¹Cd nuclei experienced an axially symmetric electric quadrupole interaction with a frequency ν _Q  = 132.4 MHz at room temperature. The samples were synthesized and doped with the probe at a pressure 8 GPa. The temperature dependence of ν _Q was shown to be linear: ν _Q (T) = 147(1 − 0.033 T) MHz. Since the value of ν _Q is very close to that known for ¹¹¹Cd in the lattice of Zn, we have checked if it could be assigned to residual Zn metal in the sample. For the Zn sample melted and doped with ¹¹¹In at 8 GPa we have obtained ν _Q  = 117.3 MHz at 300 K and 127 MHz at 80 K – both values considerably lower than that for ¹¹¹In doped Zn samples prepared at an ambient pressure. These data, and the fact that ν _Q (T) in Zn is known to follow the T ^3/2 law, allow to attribute the ν _Q value quoted above to ¹¹¹Cd nuclei at the substitutional sites with tetrahedral symmetry in the Zn sublattice of ZrZn₂.     

Application of a continuous-wave tunable erbium-doped fiber laser to molecular spectroscopy in the near infrared

Development of a continuous-wave tunable fiber laser-based spectrometer for applied spectroscopy is reported. Wide wavelength tunability of an erbium-doped fiber laser (EDFL) was investigated in the near-infrared region of 1543–1601 nm. Continuous mode-hop free fine frequency tuning has been accomplished by temperature tuning in conjunction with mechanical tuning. The overall spectroscopic performance of the EDFL was evaluated in terms of frequency tunability along with its suitability for molecular spectroscopy. High-resolution absorption spectra of acetylene (C₂H₂) were recorded near 1544 nm with a minimum measurable absorption coefficient of about 3.5×10^-7 cm^-1/Hz^1/2 for direct absorption spectroscopy associated with a 100-m long multipass cell. Detections of C₂H₂ at different concentration levels were performed as well with high dynamic detection range varying from 100% purity to sub ppmv using cavity ring down spectroscopy. A 3σ-detection-limited minimum detectable concentration (MDC) of 400 ppbv has been obtained by using the transition line P_e(22) of the ν₁+ν₃+ν₅ ¹(Π_g)-ν₅ ¹(Π_u) hot band near 1543.92 nm with a detection bandwidth of 2.3 Hz. This corresponds to a minimum detectable absorption coefficient of 6.6×10^-11 cm^-1/Hz^1/2. The sensitivity limit could be further improved by almost one order of magnitude (down to ∼60 ppbv) by use of the P_e(27) line of the ν₁+ν₃(Σ_u ⁺)-0(Σ_g ⁺)combination band near 1543.68 nm. PACS 42.55.Wd; 42.62.Fi; 07.57.Ty; 07.88.+y     

On the relationship between snowfall intensity and attenuation of short millimeter waves

We measure the dependence of radio wave attenuation at 138, 247, and 340 GHz over a near-ground radio path of length 1025 m on the snowfall intensity R. We find that the relationship between the attenuation coefficient Γ at the frequency ν and the intensity R at distinct stages of a snowfall event is close to functional and is mainly nonlinear. This relationship can be fitted well by the function Γ(ν)=γ(ν)R^m(ν) in the observed range of snowfall intensities (R is not greater than 3 mm/h in terms of the water equivalent). The dependence of Γ on R at different frequencies may change drastically as the snowfall evolves from one stage to another. The data obtained at the mentioned frequencies during the entire observation time reveal that the statistical dependence of Γ on R is close to linear. The mean specific attenuation coefficients determined using this data set turned out to be equal to 0.82, 3.3, and 5.6 dB·km⁻¹/(mm·h⁻¹) at ν equal to 138, 247, and 340 GHz, respectively. The correlation coefficients turned out to be 0.89, 0.94, and 0.98, respectively. The obtained results are compared to the data obtained in other measurements, as well as to the theoretical calculations of the attenuation based on the coupled-dipole method. Radiophysical Research Institute, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 42, No. 12, pp. 1145–1152, December 1999.     

Issues and status of “basic divertor and SOL physics” from papers and discussions

⁴⁸Ca, the lightest double beta decay candidate, has been until now the only one simple enough to be treated exactly in the nuclear shell model. Thus, theββ(2ν) half-life measurement, reported here, provides a unique test of the nuclear physics involved in theββ matrix element calculation. Enriched⁴⁸Ca sources of two different thicknesses have been exposed in a time projection chamber, and yieldT ₁ ^2/2ν =(4.3 _−1.1 ^+2.4 [stat.] ± 1.4[syst.]) × 10¹⁹ years, compatible with the shell model calculations. The consequences of this result for the shell model calculation of theββ(2ν) rate are briefly discussed. Presented by P. Vogel at the Workshop on calculation of double-beta-decay matrix elements (MEDEX’97), Prague, May 27–31, 1997. This work was funded by the US Department of Energy under contracts DE-FG03-01ER40679 and DE-FG03-88ER40397.     

Influence of anisotropy on the dispersion of surface plasmon-phonon polaritons in silicon carbide

Surface plasmon-phonon polaritons (SPPP’s) of types 3 and 4 are investigated in doped anisotropic single crystals of hexagonal silicon carbide (6H-SiC) in the orientation corresponding to K⊥C and xy⊥C. It is shown that a dispersion dependence of the type-3 SPPP’s bounded by K appears in 6H-SiC when the plasmon frequency increases to ν _p⊥⩾350 cm⁻¹. At ν _p⊥⩾400 cm⁻¹, ν _s(K) exists for type-4 SPPP’s in the frequency range Ω _∥ ⁺ <ν< _⊥ ⁺ . When the concentration of free charge carriers is increased, the dispersion curves are displaced toward higher frequencies. The conditions for the existence of type-3 and type-4 SPPP’s in 6H-SiC are determined. Fiz. Tverd. Tela (St. Petersburg) 40, 636–639 (April 1998)     

Optical properties of new organic conductors based on the BEDT-TSeF molecule (the κ-(BETS)4Hg2.84Br8 superconductor and κ-(BETS)4Hg3Cl8 Metal) in the range 300–15 K

Polarized reflectance and optical conductivity spectra of single crystals of two new isostructural organic conductors based on the BEDT-TSeF molecule, namely, the κ-(BETS)₄Hg_2.84Br₈ superconductor (T _c =2 K) and the κ-(BETS)₄Hg₃Cl₈ metal, which undergoes a smooth transition to the dielectric state near 35 K, have been obtained in the spectral region 700–6500 cm⁻¹ at temperatures of 300–15 K. At 300 K, the spectra of both compounds are nearly identical and differ from the Drude spectrum characteristic of metals. The nature of the observed difference is discussed, and the spectra are described in terms of a cluster approach with inclusion of electron-electron correlations in the Hubbard approximation combined with the Drude model. The parameters of the theory were determined, including the electron transfer integrals between molecules in a cluster. The spectra in the conducting plane of the crystals were found to be essentially anisotropic, which should be assigned to specific features of in-plane interaction between molecules. The spectra of the superconductor and the metal become increasingly different as the temperature is lowered. The spectra of the metal obtained for T<150 K exhibit splitting of the broad electronic maximum in the mid-IR region into two bands, which is accompanied by a splitting of a vibronic feature deriving from electron interaction with intramolecular BETS vibrations of ν₃(A _g ) symmetry. No such splitting is observed in the superconductor spectra with decreasing temperature. __________ Translated from Fizika Tverdogo Tela, Vol. 46, No. 11, 2004, pp. 1921–1929. Original Russian Text Copyright ? 2004 by Vlasova, Drichko, Petrov, Semkin, Zhilyaeva, Lyubovskaya, Olejniczak, A. Kobayashi, H. Kobayashi.