Line Positions and Intensities of the ν1+ ν2+ 3ν3, ν2+ 4ν3, and 3ν1+ 2ν2Bands of Ozone

Using a Fourier transform spectrometer, we have recorded the spectra of ozone in the region of 4600 cm⁻¹, with a resolution of 0.008 cm⁻¹. The strongest absorption in this region is due to the ν₁+ ν₂+ 3ν₃band which is in Coriolis interaction with the ν₂+ 4ν₃band. We have been able to assign more than 1700 transitions for these two bands. To correctly reproduce the calculation of energy levels, it has been necessary to introduce the (320) state which strongly perturbs the (113) and (014) states through Coriolis- and Fermi-type resonances. Seventy transitions of the 3ν₁+ 2ν₂band have also been observed. The final fit on 926 energy levels withJ_max= 50 andK_max= 16 gives RMS = 3.1 × 10⁻³cm⁻¹and provides a satisfactory agreement of calculated and observed upper levels for most of the transitions. The following values for band centers are derived: ν₀(ν₁+ ν₂+ 3ν₃) = 4658.950 cm⁻¹, ν₀(3ν₁+ 2ν₂) = 4643.821 cm⁻¹, and ν₀(ν₂+ 4ν₃) = 4632.888 cm⁻¹. Line intensities have been measured and fitted, leading to the determination of transition moment parameters for the two bands ν₁+ ν₂+ 3ν₃and ν₂+ 4ν₃. Using these parameters we have obtained the following estimations for the integrated band intensities,S_V(ν₁+ ν₂+ 3ν₃) = 8.84 × 10⁻²²,S_V(ν₂+ 4ν₃) = 1.70 × 10⁻²², andS_V(3ν₁+ 2ν₂) = 0.49 × 10⁻²²cm⁻¹/molecule cm⁻²at 296 K, which correspond to a cutoff of 10⁻²⁶cm⁻¹/molecule cm⁻².     

Analysis of the ν1 + ν2 + ν3 band of O3

The high resolution spectrum of the ν₁ + ν₂ + ν₃ band of O₃ in the 2800-cm⁻¹ region has been analyzed using Watson's Hamiltonian. The resulting Hamiltonian constants and previously published line intensities have been used to generate a listing of line assignments, positions, absolute intensities, and ground state energies. These should be useful for atmospheric studies.     

The ν1 and 2ν1 bands of DNSO

The infrared spectrum of DNSO has been recorded in the region of the N-D stretching fundamental vibration and of the first overtone. The results of the analysis are the following (in cm⁻¹):

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The FT-IR Spectrum of HCNO: The ν1, ν2, 2ν3, and ν2 + ν3 Band Systems

The infrared spectrum of HC¹⁵NO an isotopically substituted species of fulminic acid, has been measured in the range 1900-3600 cm⁻¹ at a resolution of 0.003 cm⁻¹ with a Bruker IFS 120 HR interferometer. More than 100 subbands have been assigned. Power series coefficients for these transitions are given. A Coriolis resonance between the levels 01002 (l = 0e) and 01010 (l = 1e) allows normally "forbidden" transitions to occur, some of which were observed and assigned. We correlate transition intensities and energies of the resonance system. Variations in the manifold of nν₅ states with excitation of other modes are compared.     

Line positions and intensities for the ν1 + ν2 and ν2 + ν3 bands of H2O

The intensities of about 90 lines of the ν₁ + ν₂ and ν₂ + ν₃ bands of H₂¹⁸O have been measured using a Fourier transform spectrum of natural water vapor. The constants involved in the rotational expansion of the transformed transition moment operators corresponding to these bands have been determined through a fit of these line intensities. The constants obtained are used to compute the whole spectrum of the ν₁ + ν₂ and ν₂ + ν₃ bands of H₂¹⁸O providing reliable line positions and intensities. For lines involving perturbed levels a comparison is given with the results obtained for H₂¹⁶O and it is shown that the results for one isotopic species cannot be transferred directly to another one.     

CO2: Global Treatment of Vibrational–Rotational Spectra and First Observation of the 2ν1 + 5ν3 and ν1 + 2ν2 + 5ν3 Absorption Bands

The effective operator approach is applied to the calculation of both line positions and line intensities of the ¹³C¹⁶O₂ molecule. About 11 000 observed line positions of ¹³C¹⁶O₂ selected from the literature have been used to derive 84 parameters of a reduced effective Hamiltonian globally describing all known vibrational–rotational energy levels in the ground electronic state. The standard deviation of the fit is 0.0015 cm⁻¹. The eigenfunctions of this effective Hamiltonian have then been used in fittings of parameters of an effective dipole-moment operator to more than 600 observed line intensities of the cold and hot bands covering the ν₂ and 3ν₂ regions. The standard deviations of the fits are 3.2 and 12.0% for these regions, respectively. The quality of the fittings and the extrapolation properties of the fitted parameters are discussed. A comparison of calculated line parameters with those provided by the HITRAN database is given. Finally, the first observations of the 2ν₁ + 5ν₃ and ν₁ + 2ν₂ + 5ν₃ absorption bands by means of photoacoustic spectroscopy (PAS) is presented. The deviations of predicted line positions from observed ones is found to be less than 0.1 cm⁻¹, and most of them lie within the experimental accuracy (0.007 cm⁻¹) once the observed line positions are included in the global fit.     

Bond-Shift Rearrangement in Solid Li3P7(Monoglyme)3: A P MAS NMR Study

The ³¹P MAS NMR spectrum of solid Li₃P₇(monoglyme)₃ has been reinvestigated over a wide temperature range (−70 to +77°C) and under conditions of better resolution (Larmor frequency of 162 MHz and spinning rate of 30 kHz) than previously measured (121 MHz and 13 kHz). At low temperatures three spinning sideband (ssb) manifolds are observed: a singlet (centered at −45 ppm relative to 85% H₃PO₄) due to the apical atom (A) of the P₇-cage trianion; a 1 : 1 : 1 triplet (at −110, −117, and −124.5 ppm) due to the negatively charged equatorial (E) atoms, and a one to two doublet (at −161 and −168.5 ppm) due to the basal (B) atoms. These results are consistent with the P₇ cage having nearly, but not perfect, C_3v symmetry. The compound appears to be well ordered in the solid state with very little structural dispersity. On heating, the NMR lines broaden and eventually coalesce into a single ssb manifold. This behavior is ascribed to bond-shift rearrangement similar to the Cope rearrangement in bullvalene. A MAS 2D exchange experiment and a quantitative analysis of the 1D NMR lineshapes indicate that, unlike in solution where the rearrangement involves a single bond shift at a time, in the solid the process involves a succession of two bond shifts: The first leads to an intermediate species in which the rearranged P₇ cage is inverted, while in the subsequent step a second bond shift takes place that also restores the original orientation of the cage in the lattice. The overall effect of the double bond shift is equivalent to cyclic permutation of the phosphorus atoms within the five member rings of the P₇-cage. The quantitative analysis of the dynamic lineshapes shows that this cyclic permutation proceeds at a different rate in one ring (k_d¹) than in the other two (k_d^2,3). The kinetic parameters for these processes are E_a¹=18.7 kJ/mol, E_a^2,3=58.0 kJ/mol, k_d¹(17°C)=k_d^2,3(17°C)=10⁴ s⁻¹. No indications for independent threefold molecular jumps of the P₇ cage were found.     

High-Resolution Infrared Spectra of the ν2, ν3, ν4, and 2ν3 Bands of SO3

New measurements are reported for the infrared spectrum of sulfur trioxide, ³²S¹⁶O₃, with resolutions ranging from 0.0015 cm⁻¹ to 0.0025 cm⁻¹. Rovibrational constants have been measured for the fundamentals ν₂, ν₃, and ν₄ and the overtone band 2ν₃. Comparisons are made with the earlier high-resolution measurements on SO₃, and the high correlation among some of the constants related to the Coriolis coupling of the ν₂ and ν₄ levels is discussed in order to understand the areas of disagreement with the earlier work. Splittings of some of the levels are observed and the splitting constant for K=3 of the ground state is determined for the first time. Other observed splittings include the K=1 levels of 2ν₃ (l=2), the K=2 levels of ν₃ and ν₄, and the K=3 levels of ν₂. The analysis shows that there are level crossings between the l=0 and l=2 states of 2ν₃ that allow one to determine the separation of the subband centers for these two states even though access to the l=0 state from the ground state is electric-dipole forbidden. This is a generalized phenomenon that should be found for many other molecules with the same symmetry. The l-type resonance constant, q₃, that causes the splitting of the l₃=±1, k=±1 levels of ν₃ also couples the l₃=0 and 2 states of 2ν₃.     

Thermogalvanic power and fast ion conduction in δ-Bi2O3 and δ-(Bi2O3)1−x(R2O3)x with R = Y, Tb---Lu

The thermogalvanic power (Seebeck coefficient) of O^2- conducting δ-Bi₂O₃ and δ-(Bi₂O₃)_1−x(Y₂O₃)_x has been measured directly as a function of temperature and partial oxygen pressure in N₂---O₂ mixtures. The of δ-(Bi₂O₃)_0.75(R₂O₃)_0.25 with R = Tb---Lu was indirectly determined using an isothermal concentration cell technique. Except for pure δ-Bi₂O₃, the heat of transport is much smaller than the activation energy for O^2- conduction for all materials. The vibrational freedom of O²⁻ ions in all δ-stabilized materials is reflected in their IR spectra at room temperature. Two prototypes of a thermogalvanic P_O2 meter were tested.     

Line Intensities in the ν1, ν3, and 2ν2 Bands of H2Se

Using a high-resolution Fourier transform spectrum of hydrogen selenide in natural abundance, about 600 intensities of lines belonging to the ν₁, ν₃, and 2ν₂ bands of H₂⁸⁰Se were measured. A least-squares fit of these intensities was performed, allowing determination of the vibrational transition moments of these bands and their rotational corrections. Finally, the first derivatives of the dipole moment with respect to the normal coordinates q₁ and q₃ were found to be ∂μ_χ/∂q₁ = (−0.5938 ± 0.010) × 10⁻¹ and ∂μ_z/∂q₃ = (0.5683 ± 0.010) × 10⁻¹ Debye, respectively.     

Al and Si MAS NMR investigations of cordierite glass, μ- and α-cordierite

²⁷Al and ²⁹Si Magic-Angle Spinning NMR results are reported for conventionally prepared glass of cordierite stoichiometry (2MgO · 2Al₂O₃ · 5SiO₂), the metastable high-quartz solid solution (μ-cordierite) and the high-temperature polymorph of cordierite (α-cordierite). Both, ²⁷Al two-dimensional (2D) quadrupole nutation experiments and ²⁷Al satellite transition spectroscopy (SATRAS) have been applied to identify two different tetrahedrally-coordinated aluminium sites (AlO₄). SATRAS has been used to extract the quadrupole interaction parameters and their distribution, the isotropic chemical shifts and the relative populations of the different Al sites. Both, the ²⁷Al and ²⁹Si NMR results, lead to the conclusion that a perfect Si/Al disorder does not exist in these investigated cordierite samples.     

Anomalous magnetotransport phenomena in θ-(BEDT-TTF)2I3

Anomalous magnetotransport phenomena have been observed in θ-(BEDT-TTF)₂I₃ crystals at temperatures below 15 K. The magnetoresistance M : (1) is a linear function of the magnetic field H, (2) is not affected by the angle between the electric current and the magnetic field, (3) but depends on the magnetic field orientation with respect to the crystal axis. Magnetoresistance is expressed as M = (aH²_a + bH²_b + cH²_c)₀^-3/2/H in terms of H = (H_a, H_b, H_c), the zero field resistivity ₀, and parameters a, b, and c which are independent of temperature and magnetic field. We have found that b a > c. Magnetoresistance up to 40 is observed for H = 7T along the b-axis at T = 1.5K.     

High-Resolution Infrared Spectroscopy of Methyl Isocyanide: The ν3, ν6, and ν7 + ν8 Bands

The vibration-rotation spectrum of methyl isocyanide (CH₃NC) has been recorded with the aid of a high-resolution Fourier transform spectrometer in the region 1370 to 1560 cm⁻¹ containing the perpendicular band of the fundamental vibration ν₆ (species E), the weaker parallel band of the ν₃ (A₁) fundamental, and the perpendicular combination band ν₇ + ν₈ (E) enhanced by Fermi resonance with ν₆. Sixteen hundred seventy well-resolved lines were assigned to 15 subbands of ν₆, 6 subbands of ν₃, and 3 subbands of ν⁻₇ + ν⁻₈. A strong x, y-Coriolis resonance between ν₃ and ν₆ and Fermi resonance between ν^±₆ and the E component ν₇ + ν₈, as well as between ν₃ and the A_1,2 components ν^±₇ + ν₈, greatly affects the spectrum. Additional weaker anharmonic interaction of ν₆ with the ν₄ + 2ν²₈ combination and higher-order rotational interactions connecting the various states were also detected in the spectrum. All of these interactions have been incorporated into a 9 × 9 Hamiltonian matrix used for modeling the upper states of the observed transitions. A set of spectroscopic constants is reported for the upper states of the bands ν₃, ν₆, and ν₇ + ν₈ and for ν₄ + 2ν²₈ which reproduces the observed lines with an overall standard deviation of 0.0012 cm⁻¹.     

The ν1 and ν3 Bands of the OOO Isotopomer of Ozone

Using 0.002 cm⁻¹ resolution Fourier transform absorption spectra of an ¹⁷O-enriched ozone sample, an extensive analysis of the ν₃ band together with a partial identification of the ν₁ band of the ¹⁷O¹⁶O¹⁷O isotopomer of ozone has been performed for the first time. As for other C_2v-type ozone isotopomers [J.-M. Flaud and R. Bacis, Spectrochim. Acta, Part A 54, 3–16 (1998)], the (001) rotational levels are involved in a Coriolis-type resonance with the levels of the (100) vibrational state. The experimental rotational levels of the (001) and (100) vibrational states have been satisfactorily reproduced using a Hamiltonian matrix which takes into account the observed rovibrational resonances. In this way precise vibrational energies and rotational and coupling constants were deduced and the following band centers ν₀(ν₃) = 1030.0946 cm⁻¹ and ν₀(ν₁) = 1086.7490 cm⁻¹ were obtained for the ν₃ and ν₁ bands, respectively.     

Oxygen isotope effect of superconducting (Nd1−xCex)2CuO4−δ system

The effect of oxygen isotope substitution on the transition temperature T_c of a superconducting (Nd_1−xCe_x)₂CuO_4−δ system was studied, where the special synthetic method was taken to minimize ambiguous factors on the oxygen concentration and to guarantee the complete substitution of ¹⁶O by ¹⁸O. The isotope exponent in the relationship of T_c∝1/M was estimated to be less than 0.15 by magnetic susceptibility measurements.     

The polarized infra-red and Raman spectra of Mg(OH)2 and Ca(OH)2

The complete polarized infra-red and Raman spectra of single crystals of calcium and magnesium hydroxide are presented. The results are largely in disagreement with those of previous workers both with regard to frequencies and to symmetry assignments. The assignments have been confirmed by study of the spectra of the deuterated counterparts of the crystals. The implications of the results for previous calculations of the dispersion curves are stressed. It is shown that there is little mixing of rotatory and translatory character among the external modes of vibration and a discussion of the origin of the Davydov splitting of the internal modes is given. The complex combination bands observed in the infra-red absorption spectrum are discussed and compared with neutron diffraction spectra.     

2D solid state NMR spectral simulation of 310, α, and π-helices

Transmembrane helices are more uniform in structure than similar helices in water soluble proteins. Solid state NMR of aligned bilayer samples is being increasingly used to characterize helical membrane protein structures. Traditional spectroscopic methods have difficulty distinguishing between helices with i to i + 3 (3(10)), i to i + 4 (alpha), and i to i + 5 (pi) hydrogen bonding topology. Here, we show that resonance patterns in PISEMA spectra simulated for these different helices show unique and striking features. The size and shape of these Polar Index Slant Angle (PISA) wheels, as well as the resonances per turn and clockwise versus counter-clockwise sequential connectivity of the resonances demonstrate how these different helical structures, if present as a uniform structure, will be readily distinguished, and characterized.     

IR-spectra of (CO2)2 dimers and collision-induced absorption of carbon dioxide in the region of the fermi doublet (ν1, 2ν2)

The positions and intensities of all vibrational transitions in the (ν₁, 2ν₂) Fermi doublet region of (CO₂)₂ dimers are obtained by means of variational method. The collision-induced absorption in compressed carbon dioxide is shown to be mainly due to dimeric absorption. Assignment of ν₁ and 2ν₂ vibrational bands in isolated CO₂ molecule is performed by consideration of the symmetries and intensities of dimeric vibrations.     

Nuclear hyperfine effects in Dy(OH)3

A crystal field analysis of the experimental data on magnetic, optical and thermal properties of Dy(OH)₃ single crystals have been published The nuclear hyperfine properties of Dy³⁺ in Dy(OH)₃ were studied using a crystal field thus obtained. The hyperfine spectra were computed from 4–20 K with a minimum number of approximations. Under a weak crystal field, the lowest electronic level is a Kramers' doublet For this highly anisotropic crystal, the magnetic hyperfine and the quadrupole interactions are both prominent The quadrupole interaction energy is temperature dependent The value of the magnetic Sternheimer factor R_hf/R is determined to be 0 14 The observed specific heat $\text{C}{}_{\mathrm{hf}}\text{R}$ arising from hyperfine interactions have been explained satisfactorily A maxima is expected at 21 mK.     

Luminescence properties of β-(Ga1−xInx)2O3 solid solutions

In this work, luminescence properties of β-(Ga_1−xIn_x)₂O₃ solid solutions were investigated with the purpose of making the new thermoluminophors for ultraviolet (UV) dosimetry. The doping of aliovalent cation admixture (Mg, Mo) in the β-Ga₂O₃ ceramic sample brings about the appearance of high-temperature thermoluminescence glow peaks with a maximum at 395 and 435 K. The maximum of the thermoluminophor photosensitivity shifts when the composition of solid solution changes.