A Study of Na2O-TiO2-SiO2 Glasses by Infrared Spectroscopy

1974 ◽  
Vol 28 (3) ◽  
pp. 256-259 ◽  
Author(s):  
Murli H. Manghnani ◽  
John R. Ferraro ◽  
L. J. Basile
Keyword(s):  
Infrared Spectroscopy ◽  
Absorption Band ◽  
Infrared Absorption ◽  
Vibrational Frequency ◽  
Silicate Glasses ◽  
Molar Ratio ◽  
Frequency Range ◽  
Weak Absorption ◽  
Infrared Absorption Spectra ◽  
The Relationship

The infrared absorption spectra of six Na2O-TiO2-SiO2 glasses in the frequency range of 1600 to 200 cm−1 are reported. These glasses, having a SiO2/Na2O molar ratio of 1.07 to 3.54, and containing 20 or 25 mole % TiO2, demonstrate two main absorptions at ∼950 cm−1 and at ∼450 cm−1. A weak absorption at ∼790 cm−1 becomes progressively weaker in intensity, and a weak shoulder at 1050 cm−1 appears with increasing Na2O content. The frequency of the absorption band at ∼950 cm−1 is found to decrease markedly and systematically with a decrease in the SiO2/Na2O molar ratio, whereas the frequency of the band at ∼450cm−1 shows a slight increase. The infrared results may be interpreted in terms of a lowering of symmetry occurring for the SiO4 units. The effect of TiO2 content on the relationship between vibrational frequency is discussed. The frequency composition curves for glasses containing 20 and 25 mole % of TiO2 intersect at SiO2/Na2O ratio ∼2. A reversal in the frequency vs SiO2/Na2O ratio relation was also found at SiO2/Na2O ∼2 for the sodium silicate glasses.

scholarly journals Helium droplet infrared spectroscopy of glycine and glycine–water aggregates

2016 ◽  
Vol 18 (40) ◽  
pp. 28082-28090 ◽  
Author(s):  
Matin Kaufmann ◽  
Daniel Leicht ◽  
Raffael Schwan ◽  
Devendra Mani ◽  
Gerhard Schwaab ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Absorption Spectra ◽  
Infrared Absorption ◽  
Superfluid Helium ◽  
Frequency Range ◽  
Helium Nanodroplets ◽  
Helium Droplet ◽  
Infrared Absorption Spectra

Infrared absorption spectra of glycine and glycine–water aggregates embedded in superfluid helium nanodroplets were recorded in the frequency range 1000–1450 cm−1.

Light-induced absorption and optical damage in Sc-, Mg-, and Zn-doped near-stoichiometric LiNbO3

2018 ◽  
Vol 27 (03) ◽  
pp. 1850030 ◽  
Author(s):  
Junsheng Li ◽  
Youwen Liu ◽  
Huijie Zhang ◽  
Liangzun Tang ◽  
Chongjun He
Keyword(s):  
Steady State ◽  
Lithium Niobate ◽  
Absorption Coefficient ◽  
Ultraviolet Light ◽  
Infrared Absorption ◽  
Doping Level ◽  
Doping Concentration ◽  
Weak Absorption ◽  
Induced Absorption ◽  
Infrared Absorption Spectra

By measuring the ultraviolet-light-induced absorption in Sc-, Mg- and Zn-doped near-stoichiometric lithium niobate (LiNbO[Formula: see text], we find that the steady-state ultraviolet-light-induced absorption coefficient changes with respect to the doping concentration. There is a strong ultraviolet-light-induced absorption when doping concentration is below its photorefractive threshold and a really weak absorption when the crystal is highly doped. We also use OH[Formula: see text] infrared absorption spectra and the transmitted light spot distortion method to verify the result. Thus, we can determine if the doping level in these doped near-stoichiometric LiNbO3 crystals is above or below their photorefractive threshold by measuring the ultraviolet-light-induced absorption.

Estimation of the infrared absorption of ZnCl2–KBr glass by molecular dynamics

1987 ◽  
Vol 2 (3) ◽  
pp. 357-360 ◽  
Author(s):  
Satoru Inoue ◽  
Mitsuru Tamaki ◽  
Hiroshi Kawazoe ◽  
Masayuki Yamane
Keyword(s):  
Molecular Dynamics ◽  
Absorption Band ◽  
Molecular Dynamic ◽  
Infrared Absorption ◽  
Experimental Results ◽  
Ir Absorption ◽  
Weak Absorption ◽  
Weak Absorption Band ◽  
Oxygen Impurities ◽  
Free Glass

Molecular dynamic calculations have been made on glasses in the ZnCl2–KBr system in order to estimate the infrared (IR) absorption of these glasses. Oxygen-free glass was estimated to be transparent up to 25 μm. Glasses containing oxygen impurities were estimated to be transparent only up to 16 μm, with a weak absorption band around 10.4 μm. This agrees with experimental results of glasses in the ZnCl2–KBr–PbBr2 system.

scholarly journals EFFECT OF DURATION OF OXYCHLORINATION ON DEGREE OF ACCESSIBILITY FOR CATALYSIS OF PLATINUM CENTERS OF PLATINUM-RHENIUM REFORMING CATALYST

2020 ◽  
Vol 63 (5) ◽  
pp. 59-64
Author(s):  
Andrey G. Starostin ◽  
Nikolai B. Khodyashev
Keyword(s):  
Carbon Monoxide ◽  
Absorption Band ◽  
Hydrogen Adsorption ◽  
Molar Ratio ◽  
Frequency Range ◽  
Alumina Support ◽  
Reforming Catalyst ◽  
Platinum Particles ◽  
Linear Vibrations ◽  
Carrier Volume

The work presents the results of a chemisorption analysis of a platinum-rhenium catalyst on an alumina support after regeneration and reduction with hydrogen. Adsorption-desorption diagrams were obtained by stepwise-pulsed chemisorption of carbon monoxide on reforming catalyst samples. With an increase in the number of carbon monoxide injections from 1 to 4, the catalyst sample is poisoned, and subsequent desorption peaks indicate the termination of the interaction. With an increase in the time of oxychlorination, the CO/Pt ratio in the carrier volume increases linearly. The effect of the oxychlorination process on the chemisorption of CO and the subsequent availability of platinum nanoparticles for catalysis has been shown. The absorption on freshly prepared platinum-rhenium catalyst samples reaches a CO/Pt molar ratio of about 0.4. The results show that the duration of oxychlorination for 16–20 h allows us to achieve the value of the ratio CO/Pt, which is in the range of 0.4-0.5. This indicates that the availability of platinum centers in its composition reaches the level of a fresh catalyst, and, on the other hand, taking into account a slight excess of this ratio, we can assume that some of the Re atoms participate in the absorption of CO molecules. The presence of finely dispersed platinum particles in the composition of the regenerated catalyst was confirmed by IR spectroscopy. The analysis of catalyst samples on an IR spectrometer in the frequency range of 1900-2200 cm-1 revealed a rather wide absorption band with a pronounced extremum at 2060 cm-1. In this frequency range, there is another, slightly pronounced extremum at 2149 cm-1. However, for samples with a short duration of oxychlorination, it did not appear. An absorption band with an extremum of 2060 cm-1 can be attributed to linear vibrations of adsorbed CO molecules on the surface of particles of metallic platinum.

Sorptive capacity of montmorillonite for hydroxy-Cr polymers and the mode of Cr complexation

Clay Minerals ◽  
1995 ◽  
Vol 30 (3) ◽  
pp. 175-185 ◽  
Author(s):  
W. E. Dubbin ◽  
Tee Boon Goh
Keyword(s):  
Infrared Spectroscopy ◽  
Absorption Band ◽  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Molar Ratio ◽  
Sorptive Capacity ◽  
Covalently Bonded ◽  
Inner Sphere ◽  
Effective Sorbent

AbstractSeparate montmorillonite suspensions were treated with CrCl3 to give seven Cr(III) concentrations. Each suspension was then titrated with 0.1 N NaOH to give a NaOH/Cr3+ molar ratio of 2.5. Montmorillonite was an effective sorbent for hydroxy-Cr species up to 1200 cmol(+)/kg; above that concentration, sorption continued, though less efficiently. However, N2-BET specific surfaces and cation exchange capacity measurements indicated that the montmorillonite could sorb significantly more than 1200 cmol(+)/kg. There was virtually no exchangeable Cr in any of the clays, suggesting that this element was covalently bonded to the siloxane surface. Infrared spectroscopy revealed a vibration at 1015–1020 cm–1 in the Cr clays which was not present in the control. This new absorption band was attributed to an attenuation of the Si–O a11 vibration caused by inner-sphere complexation of the interlayer Cr with the siloxane oxygen. Because Cr was strongly held and efficiently sorbed, montmorillonite was shown to be an effective sorbent for hydroxy-Cr polymers.

A Liquid Crystal as a Solvent in Infrared Spectroscopy

1969 ◽  
Vol 24 (5) ◽  
pp. 866-867 ◽  
Author(s):  
Torben Stroyer Hansen
Keyword(s):  
Magnetic Field ◽  
Infrared Spectroscopy ◽  
Liquid Crystal ◽  
Strong Magnetic Field ◽  
Absorption Spectra ◽  
Infrared Absorption ◽  
Maximum Degree ◽  
Degree Of Orientation ◽  
Infrared Absorption Spectra

Abstract A technique to obtain infrared absorption spectra of orientated molecules, dissolved in a liquid crystal, which is placed in a strong magnetic field, is described. The degree of orienta­tion of 4,4'-dihexoxyazoxybenzene is measured at various temperatures. The maximum degree of orientation of 4-bromo-benzonitrile and 4-cyanobenzoic acid is measured in a 10% solution in 4,4'-dihexoxyazoxybenzene to be 0.35 and 0.55, respectively.

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