Vibrational spectra oftrans-dichlorodiiodoethylene

The infrared spectra oftrans-dichlorodiiodoethylene as a solid and in solution were recorded in the region 4000–25 cm^–1. Raman spectra of the compound were obtained and semiquantitative polarization data were calculated.The mutual exclusion between the infrared and Raman frequencies are in agreement with the expectedC _2h (2/m) symmetry for this molecule. The fundamentals have been assigned and a normal coordinate analysis carried out. Thermodynamic functions and the root mean square amplitudes of vibration have been obtained.The authors wish to acknowledge financial support from theNorwegian Research Council for Science and the Humanities.     

Infrared and raman spectra of 2,4,6-trichlorobenzonitrile

The infrared and Raman spectra of 2,4,6-trichlorobenzonitrile have been measured in the solid state and in solution. A complete vibrational assignment based on aC _2v symmetry was made using the Raman polarization data and by comparison with the spectra of benzonitrile. In the solid state, the spectra are consistent with the centrosymmetric monoclinic structure reported for the molecule. Thermodynamic functions have been calculated for the temperature range 1500-200 ° K for a rigid-rotator harmonic oscillator approximation.     

Vibrational spectra and structure of chloro-fluorozirconate glasses

A series of barium chloro-fluorozirconate glasses have been prepared. Their IR absorption, IR reflectivity and Raman spectra have been measured down to 33 cm^?1. The glass transition and crystallization temperatures have also been measured. The high frequency IR absorption and Raman modes of the chloro-fluorozirconate glasses have been assigned as in fluorozirconate glasses. The IR reflection spectra of chloride-containing glasses differed from the fluorozirconates in that one band was clearly related to Cl atom motions. The structure of the glasses probably consists of zig-zag chains of ZrCl₂F₄ mixed halide octahedra plus a pure fluoride matrix whose structure is similar to that of a ZrF₄BaF₂ glass with the same composition.     

Vibrational spectra and structure of organophosphorus compounds

The infrared spectra of both CH₃OPSClF and CD₃OPSClF in the vapor phase have been recorded from 4000 to 33 cm^–1. The Raman spectra of the liquids have been recorded and a temperature study of the CD₃OPSClF spectrum has been completed. Two isomeric configurations are indicated from the low-temperature Raman spectra. The doublet due to the P=S stretching vibration has a separation of only 15 cm^–1. From the variation in the relative intensity of the doublet, an energy difference of –450 cal/mol was obtained for the two isomers. The fundamental vibrations are assigned on the basis of the band positions and isotopic shift factors. The assignments are compared to those previously given for the CH₃OPSCl₂ and CH₃OPSF₂ molecules.For part VIII,see Inorg. Chem.8, 2796 (1969).Taken in part from the thesis submitted by J. W. Clark to the Department of Chemistry for the Ph.D. degree, August 1968.We wish to thank Miss Ann Perez for recording the infrared spectra. Acknowledgement is also made to the United States Army Research Office, Durham, for the support of this research by Grant Number DA-ARO-D-31-124-G824.     

The structural and spectroscopic properties of 2,4,6-trinitro-diphenylamine and 2,4,6-trinitro-N-methyl-diphenylamine

The structural properties of 2,4,6-trinitro-diphenylamine (I) and 2,4,6-trinitro-N-methyl-diphenylamine (II) are determined by single crystal diffractometry and refined toR factors of 0.0282 for (I) and 0.04213 for (II). (I) crystallizes in the monoclinic space groupP2₁/n,Z=4, witha=11.436(5),b=7.674(2),c=15.083(4) Å,=106.47(2)°, and (II) inP2₁/c,Z=4, witha=12.654(5),b=7.371(1),c=15.083(4) Å,=101.76(2)°. The amino nitrogens show in both cases bond distances and angles typical of an sp² character. The presence of the proton on the amino nitrogen constrains ano-nitro group into a more planar geometry than that of the methyl derivative, uv/visible spectral data of both compounds are discussed. The methyl group on the amino nitrogen, of derivative (II) compared with that of (I) produces a relevant red shift which cannot be related to the simple differences in the geometry of the two molecules.     

Vibrational spectra of crystals of bismuth borates

The vibrational spectra of crystals of bismuth borates Bi₂₄B₂O₃₉, Bi₄B₂O₉, BiBO₃, and Bi₂B₈O₁₅ were obtained for the first time, and the spectra of Bi₃B₅O₁₂ and BiB₃O₆ crystals measured in the range 30–1600 cm^?1 at room temperature were refined. The lines observed were assigned to the corresponding vibrational transitions on the basis of the theoretical group analysis and comparison of the obtained results with the vibrational spectra of borates of different composition. The complication of the structure of bismuth borates with increasing content of B₂O₃ was traced by the example of vibrational spectra.     

Vibrational spectra of vapor-deposited binary phosphosilicate glasses

Room temperature infrared transmission spectra in the range 4000-250 cm^?1 of binary phosphosilicate glass (PSG) films deposited by reacting argon- or nitrogen-diluted PH₃SiH₄O₂ mixtures on heated silicon substrates at 300–400° C have been obtained across the whole composition range. In all the as-deposited binary films, an absorption at ≈1300 cm^?1 characteristics of the P=O vibration was found to persist, together with a couple of broad absorptions in the regions 1200-900 cm^?1 and 500 cm^?1. Using a differential infrared technique the broad feature in the higher frequency region has been resolved into two well-defined bands at ≈1100 and 970 cm^?1. A detailed analysis shows that the intensity variation of the differential band at ≈1100 cm^?1 conforms well, at least to 50 mol% P₂O₅, to a simple structural model that yields an analytic distribution of POSi linkages as a function of composition by assuming chemical mixing in the vapor-deposited P₂O₅SiO₂ system. Furthermore, the system may be written as (P=O)₂ O₃SiO₂ in order to emphasize the similarity of its coordination scheme with that of the B₂O₃SiO₂ system studied earlier. The nature of these CVD films has also been elucidated by thermal and water treatments.     

Vibrational spectra and phase transition in triglycine sulpho-phosphate

Infrared and single crystal Raman spectra for various polarization geometries of Triglycine Sulpho-Phosphate (TGSP) have been recorded and analysed. The bonds of hydrogen atoms in H₂SO₄ and H₃PO₄ groups are shown to be weak and the possibility of proton transfer from H₂SO₄/H₃PO₄ group is indicated. Two different types of glycinium ions are shown to be present in the unit cell. Temperature dependent Raman spectra of TGSP have been recorded. The phase transition detected around 325 K in TGSP is explained in terms of the flipping motion of the glycinium ion and of attaining a higher crystal symmetry.     

Electronic and thermodynamic properties of liquid chalcogenides

Recent measurements of various physical properties such as compressibility, electrical conductivity, optical reflectivity and nuclear magnetic resonance shift over wide temperature and pressure range are reported for liquid Se and SeTe mixtures. The observed semiconductor to metal transition for liquid Se and SeTe mixtures is accompanied by a substantial modification of the chain structure. A simple model of the transition to metallic state is proposed. The effect of charged additives on the transport properties of liquid Se is also discussed in connection with the change of the bonding configuration.     

Vibrational properties of CdGa2S4

Polarization-dependent infrared reflectivity spectra of CdGa₂S₄ are measured at 300 K in the wavenumber range from 180 to 500 cm⁻¹. The analysis of the spectra yields three E and four B modes in this frequency range. The results are compared with previously published data and a final identification of the infrared active modes in CdGa₂S₄ is proposed. It is shown that the two-phonon absorption spectra of CdGa₂S₄ can be interpreted in terms of zone-centre two-phonon combination modes. The relation between the lattice vibrational properties of chalcopyrite and defect-chalcopyrite compounds is discussed.     

Vibrational properties of glasses: Intermediate range order

This paper discusses a break-through in the calculation of the vibrational properties of disordered solids. Our approach is a refinement of the Bethe Lattice method incorporating aspects of intermediate range order.     

Chemical ordering and thermodynamic properties of HgNa liquid alloys

We have studied the thermodynamic properties and microscopic structures of HgNa liquid alloy at 673 K on the basis of regular associated solution model. The concentrations of ApB type complex in a regular associated solution of Hg and Na have been determined. We have then used the concentration of complex to calculate the free energy of mixing, enthalpy of mixing, entropy of mixing, activity, concentration fluctuations in long wavelength limit S_CC(0) and the Warren-Cowley short-range parameter α₁. The analysis suggests that heterocoordination leading to the formation of complex Hg₄Na is likely to exist in the liquid and is of a strongly interacting nature. The theoretical analysis reveals that the pairwise interaction energies between the species depend considerably on temperature and the alloy is more ordered towards Hg-rich region.     

Spectra and structure of phosphorus-boron compounds,XII1 Vibrational spectra and molecular symmetry of tetramethylbiphosphine-bisborane

The infrared (200–3500 cm^–1) and Raman (50–3500 cm^–1) spectra of two isotopic species of tetramethylbiphosphine-bisborane, (CH₃)₄P₂·2BH₃ and (CH₃)₄P₂·2BD₃, in the solid state at low temperatures have been recorded. The spectra have been interpreted in detail on the basis ofC _2h molecular symmetry. The P-B stretching modes were assigned to bands at 599 and 567 cm^–1 in the Raman and infrared spectra of the light compound, respectively. Only one P-P stretching mode was observed in the Raman spectra. The vibrational data appear to be consistent with the presence of only one conformer in the solid state, which is at variance with the conclusions from an X-ray study. Considerable splitting of the low-frequency bending modes was observed for both compounds; this splitting has been attributed to the factor group.For part XI, see J. D. Odom, V. F. Kalaskinsky, and J. R. Durig,Inorg. Chem. 14, 2837 (1975).Taken in part from the thesis of R. W. MacNamee which was submitted to the Department of Chemistry in partial fulfillment of the Ph.D. degree (1974).     

Vibrational spectra of polycrystallineMNCO (M = K,Rb, Cs)

IR and Raman spectra are reported for polycrystalline samples of the isomorphousMNCO (M=K,Rb,Cs). The lattice modes are generally assignable to the symmetry species of the factor groupD _4h by analogy with those ofMN₃, but the internal modes are not, in general, interpretable by any known practical analysis. These spectral features may be associated with the disorder of the NCO^– ions in the crystal structure.     

Vibrational spectra of the YbB<Subscript>12</Subscript> Kondo insulator

The density of phonon states for the YbB₁₂ Kondo insulator is calculated from the inelastic neutron scattering spectra of this compound. It is established that thermal vibrations of rare-earth atoms predominantly occur in the low-energy range. These atoms are most weakly bound in the crystal structure of the YbB₁₂ Kondo insulator. The high-energy part of the vibrational spectrum is determined by thermal vibrations of the boron atoms forming a rigidly connected structure of the compound. It is revealed that the temperature dependence of the intensity of the phonon peak attributed to thermal vibrations of the ytterbium atoms exhibits an anomalous behavior. This circumstance suggests that the magnetoelastic coupling occurring in the structure of the YbB₁₂ Kondo insulator is relatively strong and can contribute to the magnetic excitation spectrum of this compound.     

Photoluminescent properties and Raman spectra of ZnO-based scintillating glasses

Glasses in SiO₂–ZnO–BaO system with the different ZnO/BaO ratio were studied. In some cases, BaF₂ was introduced to substitute for BaO on the equal base. Photoluminescent spectra showed that ZnO in glass matrices behaved somewhat differently from ZnO crystals. Especially, the introduction of fluorine ions led to dramatic shift of UV emission band of glasses closer to that of ZnO crystals. Raman spectral analysis provided consistent results. In particular, Raman bands in the high frequency region are sensitive to effects of different ZnO/BaO or BaF₂/BaO ratio on structure of glasses.     

A DSC determination of the thermodynamic properties of supercooled Ni

An experimental technique allowing the achieving of a considerable supercooling of liquid Ni inside a conventional DSC calorimeter was developed. The key feature of the technique is avoiding the heterogeneous nucleation by coating the sample’s surface with a thin oxide layer. The technique developed allowed measuring the enthalpy of crystallization and calculating the heat capacity and the Gibbs energy of pure Ni.     

Vibrational and structural properties of glass and crystalline phases of TeO2

A wide-spread opinion regarding the paratellurite (-TeO₂) lattice as a parent structure of TeO₂ glass is questioned. Consequently, the Raman and infrared spectra of TeO₂ glass are contrasted with those of three crystalline lattices (, β, γ) of TeO₂ and their vibrational state density distribution functions. Additionally, the data on the crystallization of the liquid and glassy states of TeO₂ are considered. As a result, of the known crystalline phases of TeO₂, the γ-phase is proposed as the closest to TeO₂ glass.