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 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.     

Raman spectra and structure of sodium aluminogermanate glasses

Polarized Raman spectra of x NaAlO₂·(100 ? x) GeO₂ glasses (x = 0, 5, 10, 15, 20, 25, 33, 42, and 50) are presented. Analyses of the Raman data indicate that the aluminogermanate glasses have three-dimensional network structures consisting of interconnected AlO₄ and GeO₄ tetrahedra; Na⁺ ions are present in cavities and charge balance the Al³⁺ ions. Systematic changes are observed in the frequencies, intensities and polarization characteristics of spectral bands with variations in the NaAlO₂ content of these glasses. The antisymmetric stretching mode [ν_as (TOT), where T = Al, Ge] in the high-frequency region of the spectra (800–1000 cm^?1) appears as a doublet consisting of well-defined bands in the spectra of glasses along the entire join. Both components of the high-frequency doublet shift to a lower frequency with increasing NaAlO₂ content, indicating that the ν_as (GeO₄) and ν_as(AlO₄) stretching modes are coupled. The variations in the TO force constants and TOT bond angles with change in composition most likely cause the bands to shift. The frequencies of the Raman bands of sodium aluminogermanate glasses are compared with those of the corresponding bands in isostructural sodium gallogermanate glasses. On the basis of this comparison, the origin and delocalization of the vibrational modes producing characteristic Raman bands in the spectra of these glasses are discussed. The changes observed in the Raman spectra of aluminogermanate glasses with variation in NaAlO₂ content are analogous to those observed in the spectra of glasses along the NaAlO₂SiO₂ join.     

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.     

Octahedral fluoride glasses: Raman spectra and structure of niobium pentafluoride

Raman spectroscopy is used to characterize the NbF₅ phases in the temperature range 80–500 K. A new clear glass is formed by quenching the melt to liquid nitrogen temperatures having a glass transition at ～206 K and crystallization at ～233 K. For all phases including the melt, the glass, the supercooled liquid, the crystalline solid and the gas, the Raman spectra show a rather common high frequency band at ～760 cm^?1 which is attributed to the Nb–F terminal frequency of partially bridged ‘NbF₆’ octahedra. Based on the systematics of the Raman spectra for all phases and the literature physicochemical data a model is proposed for the glass and the liquid phases where ‘NbF₆’ octahedral bridged in cis and/or trans configurations form a variety of cyclic and/or chain structures which intermix building up the overall structure. At exceptionally low energies (<11 cm^?1) a rather weak in intensity Boson peak is observed in the glass which shifts to even lower energies with increasing temperature. Librational and/or tortional motions of the bridged octahedra participating in the glass structure are possible candidates for the origin of this peak.     

Optical spectra of glasses

This presentation focuses on several ways in which structural and dynamical information can be obtained from optical spectroscopy by examining results of infrared and Raman studies of selected oxide glasses. Though these studies represent only a small fraction of the work on most of the glasses mentioned, and many other important forms of optical spectroscopy are not treated here, they illustrate useful approaches to the study of amorphous materials by optical methods.     

Vibrational spectroscopy study of niobium germanosilicate glasses

A series of glasses in the (Ge,Si)O₂–Nb₂O₅–(Na,K)₂O system were prepared by melting and casting. Their density and characteristic temperatures were determined by Differential Thermal Analysis (DTA) and their structure was analyzed by infrared and polarized Raman spectroscopies. DTA data have indicated an increased glass thermal stability with the replacement of GeO₂ by SiO₂. Kramers–Kronig analysis of the infrared specular reflectance data indicated a strong ionic character for the germanosilicate glasses. The Raman spectra of germanosilicate compositions were generally dominated by an intense Boson peak at ∼72 cm⁻¹ and a high frequency, polarised peak at ∼880 cm⁻¹, related to NbO₆ octahedra with at least one non-bridging oxygen. The germanosilicate structure appears to be formed by alternating GeO₄ tetrahedra and NbO₆ octahedra, in addition to SiO₄ tetrahedra.     

Vibrational spectroscopic studies of some lead silicate glasses

Results are presented of measurements on the infrared and laser Raman spectra of some lead silicate glasses of general formula (PbO)_x(SiO₂)_y.For the infrared spectra, the frequency dependence of the imaginary component of the complex dielectric constant was determined from a Kramers-Krönig analysis of the reflectance spectra of the glasses at normal incidence. Apparently the addition of small amounts of PbO to vitreous silica serves to modify the continuous three-dimensional silica network; whereas in those glasses with a high lead content, the influence of the cation, Pb²⁺, appears to lie between that of network former and network modifier.     

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 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.     

Optical spectra of borate glasses containing Ti and Co in relation to their structure

The optical absorption spectra of borate glasses of the base composition (mol%) 35 (Na₂O+BaO)·65 B₂O₃, to which Ti and Co ions were introduced, have been measured in the range 190–900 nm. The addition of increasing amounts of TiO₂ up to 16 g/100 g glass, introduces an intense charge transfer band in the UV region that shifts towards longer wavelengths without imparting any coloration to the glass samples.Titanium ions are present as the Ti⁴ state and its addition produces glass of more coherent structure. The cobalt ions are found to be present in two symmetries; as CoO₆ units with absorption bands (denoted here as bands a and b) around 525–530 nm and 580–595 nm (respectively), and as CoO₄ units with absorption bands (denoted here as band-c) around 620–635 nm. Replacing Na ions by Ba ions or increasing the TiO₂ content favours the conversion of CoO₄ units into the CoO₆ ones.     

Vibrational states and disorder in continuously compressed model glasses

We present in this paper a numerical study of the vibrational eigenvectors of a two-dimensional amorphous material, previously deeply studied from the point of view of mechanical properties and vibrational eigen-frequencies [7], [8], [9] and [10]. Attention is paid here to the connection between the mechanical properties of this material in term of elastic heterogeneities (EH), and how these inherent heterogeneous structures affect the vibrational eigenvectors and their plane waves decomposition. The systems are analysed for different hydrostatic pressures, and using results from previous studies, a deeper understanding of the boson peak scenario is obtained. The vibrational spectrum of a continuously densified silica glass is also studied, from which it appears that the pulsation associated with the boson peak follows the same pressure dependence trend than that of transverse waves with pulsation associated with the EH characteristic size.     

Vibrational spectra and thermodynamic properties of 2,4,6-tribromobenzonitrile

The infrared and Raman spectra of 2,4,6-tribromobenzonitrile have been recorded in the solid state and in solutions. Assignments of the fundamental vibrations based on Raman polarization data and comparison with the spectra of benzonitrile and its trichloro derivative are given and discussed. The thermodynamic functions have been evaluated for a rigid-rotor harmonic oscillator approximation at several temperatures.     

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.     

Optical spectra of sodium phosphate glasses

The visible, infrared, and ultraviolet spectra of seven glasses in the Na₂OP₂O₅ binary system were obtained. Changes in spectra were related to structural changes occurring the glass. Dopant ions Co²⁺, Cu²⁺, and Pb²⁺ were used to infer structural changes occurring as the metaphosphate composition was crossed going from pyrophosphate compositions into ultraphosphate compositions. The presence of chemically bound water was found to cause the overall modifier-to-former ratio to remain constant for glasses containing greater than 65 mol.% P₂O₅.     

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.     

The effects of ZnCl2 and ErCl3 on the vibrational spectra and structure of tellurite glasses

A series of zinc tellurite glasses, containing up to 40 mol% ZnCl₂ and doped with 1–10 mol% ErCl₃, was prepared by melting and casting and their structure was analyzed by polarized Raman and variable incidence infrared reflection spectroscopies. Kramers–Kronig analysis of the infrared reflectivity led to the identification of the vibrational mode components. The Raman spectra are dominated by an intense, depolarized boson peak at ∼45 cm⁻¹ and a high frequency, polarized peak at ∼767 cm⁻¹. The introduction of ZnCl₂ and ErCl₃ modifiers led to a blue shift of the high frequency peak, while the intensity of the boson peak was found to increase continuously with the Er³⁺ content. It is shown that the erbium and zinc compounds both break TeOTe bonds, introducing non-bridging chlorine species, connected mostly to the zinc atoms.     

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.     

Formation and structure of titanate glasses

The formation of high titanium oxide (30–60 wt%) containing glasses was studied. Stable titanate glasses with high content of TiO₂ and BaO could be obtained even without other glass-forming oxides. It is demonstrated that the coloration of titanate glasses with high content of TiO₂ is due to oxygen loss during the melting. A systematic study of controlling melting and heat treatment conditions led to the successful decoloration of titanium oxide containing glasses. Infrared spectra and X-ray diffraction studies showed that Ti⁴⁺ in titanate glasses is in sixfold coordination. Phase separation was observed by electron microscopy when the titanate glasses were heat-treated at the temperature above T_g. The crystallization of titanate glasses is generally preceded by phase separation. The obtained crystalline phases are mainly different titanates.     

Raman and optical reflection spectra of germanate and silicate glasses

Germanate and phosphosilicate glasses made in oxygen surplus conditions were studied by Raman and optical reflection methods. We found that the optical reflection spectra of the germanate glasses are quite similar to the one those of a GeO₂ crystal with the α-quartz structure. The reflection of phosphosilicate glasses is very close to silica glass-related spectra. Hence, the determining influence of the tetrahedral structure on reflection spectra is revealed. The Raman spectra of germanate samples are similar to those reported the one known in the literature. Octahedral entities, namely bands similar to stishovite vibration modes, were difficult to detect in phosphosilicate glasses through Raman spectroscopy.