A theory of the broadening of the infrared absorption spectra of hydrogen-bonded species. I

1974 ◽  
Vol 337 (1609) ◽  
pp. 167-197 ◽  
Keyword(s):  
Infrared Absorption ◽  
Formal Method ◽  
Subsequent Paper ◽  
Complex Energy ◽  
Vibrational States ◽  
Absorption Bands ◽  
Vibrational Predissociation ◽  
Energy Eigenvalues ◽  
Infrared Absorption Spectra ◽  
Hydrogen Bonded

A theory of the intramolecular contributions to the broadening of the v (XH) absorption bands of hydrogen-bonded species is proposed, which is able to describe both vibrational predissociation and the formation of sum and difference bands. A formal method is developed for finding the wavefunctions and complex energy eigenvalues of quasi-stationary excited vibrational states of a linear triatomic system with realistic interactions. The theory is applied to the Me 2 O.HCl system. It is found that predissociation broadening is negligible. The calculation of combination band intensities, and of the spread in energy of terms within such bands, will be reported in a subsequent paper.

scholarly journals Оптические свойства фазопеременных материалов системы германий--сурьма-теллур составов Ge-=SUB=-14-=/SUB=-Sb-=SUB=-29-=/SUB=-Te-=SUB=-57-=/SUB=- и Ge-=SUB=-15-=/SUB=-Sb-=SUB=-15-=/SUB=-Te-=SUB=-70-=/SUB=- в дальнем инфракрасном диапазоне

2021 ◽  
Vol 55 (7) ◽  
pp. 542
Author(s):  
В.А. Рыжов ◽  
Б.Т. Мелех ◽  
Л.П. Казакова
Keyword(s):  
Amorphous Alloy ◽  
Infrared Absorption ◽  
Crystalline State ◽  
Room Temperature ◽  
Torsional Vibrations ◽  
Phonon Modes ◽  
Absorption Bands ◽  
Structural Units ◽  
Chalcogenide Alloys ◽  
Infrared Absorption Spectra

Abstract Infrared absorption spectra of chalcogenide alloys of the GST system with the compositions Ge14Sb29Te57 and Ge15Sb15Te70 in the amorphous and crystalline state were measured and analyzed in the range of 20 – 400 cm– 1 (0.6 – 12 THz) at room temperature. Absorption at these frequencies is due to the manifestation of correlated torsional vibrations of structural units of the amorphous alloy and phonon modes of the crystal. The performed assignment of absorption bands and the revealed differences in the IR spectra make it possible to more confidently represent the possible molecular mechanism of reversible amorphous-crystalline transformations in the studied phase-changing materials

Infrared Absorption Spectra and Their Correlation with the Ti-O Bond Length Variations for TiO2 (Rutile), Na-Titanates, and Na-Titanosilicate (Natisite, Na2TiOSiO4)

1995 ◽  
Vol 49 (11) ◽  
pp. 1646-1651 ◽  
Author(s):  
Gow-Weng Peng ◽  
Shou-Kang Chen ◽  
Hok-Shing Liu
Keyword(s):  
Bond Length ◽  
Absorption Spectra ◽  
Infrared Absorption ◽  
Ir Absorption ◽  
Crystalline Solids ◽  
Absorption Bands ◽  
Structural Units ◽  
Structure Correlations ◽  
Geometric Setting ◽  
Infrared Absorption Spectra

The mid-infrared absorption spectra (400–1200 cm−1) of four TiO2-bearing crystalline solids, in the form of rutile (TiO2), Na-titanates (Na2Ti6O13/ Na2Ti3O7), and natisite (Na2TiOSiO4), are presented, providing a clear illustration of their differences in IR band structure (band pattern). Two sharp characteristic peaks of IR absorption bands of natisite have been noted at 725 and 624 cm−1, representing the internal vibration modes of TiO5 (normal) and SiO4 structural units, respectively, and obtainable by comparison with that of Ca-titanosilicate (CaTiOSiO4), NTS glass (Na2O-TiO2-SiO2), and low-cristobalite (SiO2). The tested series of TiO2-bearing crystalline solids has been helpful in presenting a case study in support for the generalization of IR spectra/structure correlations, showing that vibrational spectroscopy can be useful for understanding the crystal chemistry of crystalline solids in terms of the geometric setting of molecular structural units and chemical bonds. It has been qualitatively demonstrated that the Ti-O bond length variations may be broadly correlated with the complexity of IR absorption bands of four TiO2-bearing solids having great diversity in both chemical composition and crystalline structure.

The Infrared Absorption of Rubber and Related Hydrodcarbons

1937 ◽  
Vol 10 (1) ◽  
pp. 120-120
Author(s):  
Dudley Williams
Keyword(s):  
Infrared Absorption ◽  
The Other ◽  
Absorption Bands ◽  
Intense Band ◽  
Vulcanized Rubber ◽  
Intense Absorption ◽  
Infrared Absorption Spectra ◽  
Low Sulfur Content ◽  
Low Sulfur ◽  
Long Chain

Abstract The infrared absorption spectra of rubber and certain related hydrocarbons have been studied by using extremely thin films of the samples as absorbing layers. In the spectra of styrene, isoprene, and cymene intense absorption bands appear at 3.4µ, 6.2µ, and 7.0µ and also weaker bands between 7µ and 9µ. These bands were common to most of the hydrocarbons studied. The principal variations in the spectra of the compounds mentioned above are found in bands whose positions vary between 5.5µ and 5.7µ in the different compounds. In the case of “pure gum” rubber a band was found at 5.8µ and in a vulcanized rubber of low sulfur content corresponding absorption occurs at 6.0µ. At all other wave-lengths between 2.5µ and 9.0µ the absorption spectrum of rubber has a striking resemblance to that of isoprene, a result which is in agreement with the chemist's model of the rubber molecule as a long chain of isoprene units. The absorption in the 5.8µ region probably arises from a mechanism which is intimately connected with the process of polymerization. The spectrum of polymerized butadiene contains strong bands at 5.5µ and 6.0µ and also less intense bands beyond 7.0µ, whose positions are not the same as those in the spectrum of natural rubber. Rubber hydrochloride has a very intense band at 8.4µ which is not characteristic of the other hydrocarbons studied.

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