6 Infrared emission spectroscopy

Bernath, P. F.

doi:10.1039/b001200i

Cited by 34 publications

(36 citation statements)

References 414 publications

(323 reference statements)

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“…Ideally only photons emitted by the sample are detected ("zero background"), free from the noise produced by the continuum lamp in an absorption experiment. This improvement in sensitivity is particularly useful for the spectroscopy of transient molecules because of their intrinsically low concentrations [53]. In the case of hybrid silicas, this methodology can be successfully employed to evaluate the thermal stability of materials.…”

Section: Applications Of Molecular Spectroscopy To Current Research Imentioning

confidence: 99%

Fourier Transform Infrared and Raman Characterization of Silica-Based Materials

Capeletti¹,

Zimnoch²

2016

Applications of Molecular Spectroscopy to Current Research in the Chemical and Biological Sciences

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Fourier Transform Infrared and Raman are powerful techniques to evaluate silica and hybrid silica structure. It is possible to evaluate the silica network formation along the hydrolysis and condensation reactions in terms of siloxane rings formation and Si-O(-Si) angle deformation due to the introduction of organic groups, the employed synthetic route or encapsulated species interaction. The siloxane four-or six-membered rings imply in a more rigid or flexible network, respectively, in order to accommodate the organic groups. A structural analysis of the materials is of high importance, since interactions between the encapsulated molecules and the matrix are critical for the device performance, such as sensors. This type of device needs the permeation of an analyte to activate the encapsulated receptor molecules inside the silica structure. Fourier transform infrared spectrometry can be also used to determine parameters of the silica network as a function of the hydrophilicity/hydrophobicity degree and the siloxane ring structure with respect to thin film porosity. This silica structural analysis is reviewed along the text in a tentative of better exploring the data resulting from these powerful techniques. In addition, the functionalization of silica structures by the use of organoalkoxysilanes, which is important to the creation of high-specific materials, can be well described by these two complementary techniques. The Si-C bonds and the maintenance of the organic substituents such as methyl, octyl, octadecyl, vinyl, phenyl, aminopropyl, mercaptopropyl, isocyanatopropyl, iodopropyl, chloropropyl and glicydoxypropyl could be evaluated after the sol-gel synthesis process. The literature regarding silica vibrational spectroscopy is also explored creating a data bank of wave numbers for the most important bonds for different types of silica and hybrid silica materials obtained by different synthetic routes.

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Section: Applications Of Molecular Spectroscopy To Current Research Imentioning

confidence: 99%

Fourier Transform Infrared and Raman Characterization of Silica-Based Materials

Capeletti¹,

Zimnoch²

2016

Applications of Molecular Spectroscopy to Current Research in the Chemical and Biological Sciences

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“…The ratio of intensities of these maxima changed if the mixture composition was changed. With respect to the maximum at λ ~ 2200 nm, it was obviously related to emission of SrO molecules from the transition A ′ 1 Π → X 1 Σ + [6]. The maximum near 4000 nm was related, in our opinion, to emission of the solid phase.…”

mentioning

confidence: 92%

“…The quartz objective (6) could concentrate flame emission from the studied zone on the optical entrance of the light guide (7) that transmitted it onto the entrance slit of the spectrometer (4). Attenuating neutral light filters (8) were installed before the objective (6) in order to optimize the slit illumination level. Spectra were recorded by a Fig.…”

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confidence: 99%

Emission spectra of pyrotechnic mixtures of heat flux simulators

et al. 2012

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Comprehensive optical spectroscopic studies of the combustion process of solid-state pyrotechnic mixtures based on Mg and Sr(NO 3 ) 2 have been carried out. Emission spectra of the mixtures in the ultraviolet, visible, and infrared wavelength regions have been studied under various atmospheric conditions taking into account radiation transfer in air along an optical path of observation up to 5 km long.Introduction. Pyrotechnic mixtures (PM) based on a solid combustible and oxidant that are capable of creating an optical, thermal, acoustic, or reactive effect as a result of slow combustion have been used in various popular capacities since antiquity. The scientific and technical revolution of the XIXth century stimulated their use in marine and aviation transportation, the cinema, agriculture, industry, and the military [1, 2]. Pyrotechnic IR emitters have recently begun to be widely used. In most instances, the pyrotechnic emitters must provide rather intense radiation in a certain spectral range for a given time period in order to solve the particular problems.Metals (Mg, Al, and their alloys; more rarely, Ti and Zr), hydrocarbon mixtures (kerosene, hydrocarbons, diesel oil), carbohydrates (starch), wood, and sawdust are mainly used as the combustible material in PM; nitrates, chlorates, and perchlorates of alkali and alkaline-earth metals and oxides of certain metals (Fe 3 O 4 , MnO 2 ), as the oxidants [1]. Binders, retardants, and stabilizers are added to PM in order to give them the required mechanical properties and to ensure their safe preparation and storage. Several problems resolved using PM require the appropriate coloration and brightness amplification of the flame emission arising during their combustion in air. The brightness of the flame emission and its spectral and energy characteristics can be controlled by enriching the PM in various salts and organic dyes. Emission spectra of PM have been studied most in the UV and visible regions [3]. The emission properties of PM in the IR region are practically unstudied.The goal of the present work was to study comprehensively emission spectra of slowly combusting PM in the UV, visible, and IR regions taking into account radiation transfer in air along the observation path.Experimental. The studied PM contained Sr(NO 3 ) 2 as the oxidant and finely dispersed Mg powder (grade MPF-4, GOST 6001-79) as the combustible material. Furthermore, synthetic and natural binders (iditol, resin) and various colored-flame additives (SrCl 2 , S) were introduced into the composition. The percent content of the used ingredients varied during the investigations and were 45-55% for Sr(NO 3 ) 2 ; 20-40, Mg; 2-10, iditol or resin; and 5-15, SrCl 2 and S. A drying procedure in an electric cabinet at temperatures established by technical instructions was used to remove moisture from SrCl 2 and Sr(NO 3 ) 2 . The PM was incapable of absorbing moisture after granulation because it was soaked with iditol or resin.The prepared PM was pressed evenly throughout the whole volume into a...

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“…With the advent of high-resolution Fourier-transform spectrometers and sensitive semiconductor detectors, over the last two decades infrared emission spectroscopy has become a powerful method for spectroscopic studies of vibration-rotation and electronic transitions in transient molecules [1]. In our laboratory, we have applied this technique mostly to the study of inherently weak spin or symmetry ''forbidden'' transitions from low-lying metastable states of diatomic and triatomic radicals generated and excited by chemical reactions or energy transfer processes in fast-flowing gaseous reaction systems.…”

Section: Introductionmentioning

confidence: 99%