Infrared absorption studies

Sheinker et al. thoroughly studied protomeric equilibria by a study of the infrared properties of 2-aminothiazoie and 2-imino-4-thiazoline derivatives (94, 105, 119). His results confirm that the amino form is predominant, a conclusion also drawn from the infrared absorption study of 2-anilinothiazole (120) and 2-heteroarylaminothiazoles (1569). 

Infrared absorption studies have shown that correlates with an absorption at 3 p.m associated with an OH-stretching frequency (20). Indeed, infrared absorption provides a useful tool for evaluation in rapid production quaUty control. Infrared and other studies show that degradation is caused by proton inclusion in the grown quartz. 

Infrared absorption studies of CO on platinum shows two bands near... 

Allyl Free Radicals. Ayscough and Evans (3) have recently studied, by ESR measurements, the types of allylic free radicals produced by gamma-irradiation of several monomeric olefins. In irradiated polyethylene the allyl free radical is quite stable, persisting for several months at room temperature (31). The presence of these allyl free radicals is most noticeable in the case of high density polyethylene, and this type of free radical is undoubtedly the cause of the slow oxidation of polyethylene at room temperature, which lasts for 40 or more days after irradiation (10). Williams and Dole (40) could observe little if any oxidation of low density polyethylene when it was exposed to air after irradiation. By oxidation we mean formation of carbonyl groups as detected by infrared absorption studies at 1725 cm"1. Parenthetically, it should be noted that adding an oxygen. molecule to a free radical produces initially another type of free radical, a peroxy free radical, but in this paper we shall not discuss free radicals of this or any other types except those of hydrocarbons. 

Dougherty TP, Heilweil EJ. Ultrafast transient infrared absorption studies of M(CO)6 (M = Cr, Mo, W) photoproducts in n-hexane solution. Chem Phys Lett 1994 227 19-25. 

Marton J, Adler E, Persson K-E (1961) Carbonyl groups in lignin IV Infrared absorption studies and examination of the volumetric borohydnde method Acta Chem scand 15 384-397... 

Matrix Bonding Infrared Absorption Studies. It is possible that some form of reaction could occur between liquid sulfur and the hydrated cement phases to produce a chemical bond which would contribute to the strength of the composite, perhaps more noticeably with filling of the... 

Infrared absorption studies of crystalline sugars and lyophilizates of equilibrated sugars have been made. For anomeric pairs, two groups of sugars were detected. The first group (D-glucose, L-rham-nose, and D-mannose) had spectra for the lyophilizate of the equilibrium solution that could be accounted for by those of the individual crystalline anomers. The second group (D-lyxose and D-talose) had absorption bands additional to those of the known crystalline anomers. 

Last JT (1957) Infrared-absorption studies on barium titanate and related materials. Phys Rev... 

Although the basic model looks very good, the actual situation must be more complex since faujasite and Y zeolites cannot have full long-range order. The actual positions of the H atoms must vary somewhat from 1 unit cell to another, and such variations may lead to particularly active catalytic sites in just a few of the unit cells. Hopefully, singlecrystal infrared absorption studies, similar to those carried out for many silicates, will yield data on the orientation of the OH groups, thereby testing the Olson-Dempsey model. 

A number of infrared absorption studies on the purified epidermal protein are described. In combination with the X-ray diffraction data, they entirely confirm the recent advances in the definition of absorption spectra, which are characteristic of a- and /3-type proteins and polypeptides, in terms of the kinds of dichroism and the frequency changes associated with the (3 form. It is pointed out that as the dichroism changes with the a — change it is not possible to read off the relative amounts of a and from the absorption spectra because of the differences in the orientation of the absorbing bonds with reference to the plane of the film. In the absorption spectra of highly stretched epidermin, where... 

N,T. McDevitt, W.L, Baun, Infrared absorption study of metal oxides in the low frequency region... 

In conclusion, infrared absorption studies on irradiated alkah azides indicate the presence of a triatomic defect of D3J symmetry at 77°K which could be either a trapped N3 excitation or a N3" center. Raman scattering experiments with 6328 A excitation show a resonance-enhanced spectrum for a crystal of KN3 irradiated at 77°K, with a fundamental peak at 307 cm". This peak can be related to a local mode associated with the NJ defect. 

Infrared absorption studies have shown that most biogenic silica is present as gel or dissolved silica. However, emission spectroscopy studies have indicated that some of the soluble silica found in animals is bound to organic molecules, such as glycosaminoglycans, whose structure has yet to be identified(51). 

Haris, M. J. Salje, E. K. H. (1992). The Incommensurate Phase of Sodium Carbonates An Infrared Absorption Study. Journal of Physics Condensed Matter, Vol.4, No.l8, pp. 4399-4408. 

Photoinduced infrared absorption studies show that the photoinduced infixired modes are much weaker in intensity, than the photoinduced electronic transition [23], in contrast to the behavior of polyacetylene [51,52] and polythiophene [6]. Analysis, within the amplitude mode formalism [53], indicates that the polarons are massive, > or -60 m, while use of bond order [54] or Holstein [55] polaron formalisms leads to an even larger estimate of the mass of the polarons. Photoexcitation, into either the exciton peak or the 7C-to-7t peak of emeraldine base, produces essentially identical long-lived photoinduced infrared modes [29]. The long-lived photoinduced spectra of the leucoemeraldine base are much weaker. Similarly, the photoinduced infrared absorptions in the pemigraniline base are much weaker, than the photoinduced electronic transitions, again indicating massive photoinduced defects [30]. 

Pyridine extraction of coal appears to afford, as indicated by infrared absorption studies, a two-component system, one rich in carbonyl and hydroxyl functions and the other in nonaromatic... 

Marquardt Index n. In an infrared-absorption study of the cure advancement of a phenolic resin, the Marquardt index is the numerical difference in percent transmission between the absorption peaks at 12.2 and 13.3 pm. As the resin cure progresses, the intensity of the 13.3-pm absorption increases more rapidly than that of the initially stronger 12.2-pm peak. 

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