Laser-initiated chlorine/hydrocarbon chain reactions: time-resolved infrared emission spectra of product vibrational excitation

1982 ◽  
Vol 86 (25) ◽  
pp. 4962-4973 ◽  
Author(s):  
David J. Nesbitt ◽  
Stephen R. Leone
Keyword(s):  
Vibrational Excitation ◽  
Emission Spectra ◽  
Hydrocarbon Chain ◽  
Infrared Emission ◽  
Time Resolved ◽  
Chain Reactions

Distribution of Vibrational States of CO2in the Reaction O(1D) + CO2from Time-Resolved Fourier Transform Infrared Emission Spectra

2009 ◽  
Vol 113 (15) ◽  
pp. 3431-3437 ◽  
Author(s):  
Hui-Fen Chen ◽  
Hung-Chu Chiang ◽  
Hiroyuki Matsui ◽  
Soji Tsuchiya ◽  
Yuan-Pern Lee
Keyword(s):  
Fourier Transform ◽  
Emission Spectra ◽  
Fourier Transform Infrared ◽  
Infrared Emission ◽  
Vibrational States ◽  
Time Resolved

scholarly journals Laser Induced Chemical Reactions in Combustion and Industrial Processes

1986 ◽  
Vol 6 (2) ◽  
pp. 125-147 ◽  
Author(s):  
J. Wolfrum
Keyword(s):  
Chemical Reactions ◽  
Potential Energy Surfaces ◽  
Vibrational Excitation ◽  
Rapid Development ◽  
Radical Chain ◽  
Time Resolved ◽  
Chain Reactions ◽  
Rate Determining Step ◽  
Energy Expense ◽  
Energy Surfaces

The rapid development of powerful UV-laser sources allows the investigation of macroscopic and microscopic details of elementary chemical reactions important in combustion processes. Experimental results on the effect of selective translational and vibrational excitation of reactants in elementary combustion reactions using laser photolysis and time-resolved atomic line resonance absorption, laser-induced fluorescence and CARS spectroscopy are compared with the results of theoretical studies on ab initio potential energy surfaces and thermal rate parameters. Thermal elimination of hydrogen chloride from 1,2-dichloroethane and 1,1,1-chlorodifluoroethane is a main industrial route to some important monomer compounds. Inducing these radical chain reactions by UV-exciplex laser radiation offers the advantage that a monomolecular process with low activation energy becomes the rate determining step. This allows lower process temperatures with decreasing energy expense and avoiding the high temperature formation of byproducts.

The Use of Ratio-Recording Interferometry for the Measurement of Infrared Emission Spectra: Applications to Oxide Films on Copper Surfaces

1975 ◽  
Vol 29 (6) ◽  
pp. 496-500 ◽  
Author(s):  
D. Kember ◽  
N. Sheppard
Keyword(s):  
Emission Spectra ◽  
Black Body ◽  
Infrared Emission ◽  
Thin Layers ◽  
Oxide Surface ◽  
Surface Layers ◽  
Selective Reflection ◽  
Copper Surfaces ◽  
Emission And Absorption Spectra ◽  
Direct Correspondence

Infrared emission spectra from metal samples with oxide surface layers are shown to be very advantageously studied using the spectrum-ratioing facility of a recording infrared interferometer. The emission from a given sample is ratioed against that from a black-body emitter at the same temperature so as to give emittance as a function of wavenumber directly. This method has very useful application to irregularly shaped metal emitters. In the absence of selective reflection there is a direct correspondence between emission and absorption spectra for thin layers of an emitting substance. However, the presence of selective reflection leads to reduced emission and to considerable differences in the appearance of “absorption” and emission spectra in regions of strong absorption. Emission spectra obtained from copper plates heated, above 150°C, for different periods in air are shown clearly to indicate the presence of cuprous, Cu(I), and cupric, Cu(II), oxides in the surface layer.

Optical, electrochemical and third-order nonlinear optical studies of triphenylamine substituted zinc phthalocyanine

2016 ◽  
Vol 20 (08n11) ◽  
pp. 1173-1181 ◽  
Author(s):  
Narra Vamsi Krishna ◽  
Puliparambil Thilakan Anusha ◽  
S. Venugopal Rao ◽  
L. Giribabu
Keyword(s):  
Nonlinear Optical ◽  
Emission Spectra ◽  
Optical Emission ◽  
Soret Band ◽  
Laser Pulses ◽  
Zinc Phthalocyanine ◽  
Third Order ◽  
Time Resolved ◽  
Nlo Properties ◽  
Scan Data

Zinc phthalocyanine possessing triphenylamine at its peripheral position has been synthesized and its optical, emission, electrochemical and third-order nonlinear optical (NLO) properties were investigated. Soret band was broadened due to the presence of triphenylamine moiety. Electrochemical properties indicated that both oxidation and reduction processes were ring centered. Emission spectra were recorded in different solvents and the fluorescence yields obtained were in the range of 0.02–0.17 while the time-resolved fluorescence data revealed radiative lifetimes of typically few ns. Third-order NLO properties of this molecule have been examined using the Z-scan technique with picosecond (ps) and femtoseocnd (fs) pulses. Closed and open aperture Z-scan data were recorded with 2 ps/1 50 fs laser pulses at a wavelength of 800 nm and NLO coefficients were extracted from both the data. Our data clearly suggests the potential of this molecule for photonics applications.

Infrared emission spectra of BeH2 and BeD2

2003 ◽  
Vol 118 (8) ◽  
pp. 3622-3627 ◽  
Author(s):  
A. Shayesteh ◽  
K. Tereszchuk ◽  
P. F. Bernath ◽  
R. Colin
Keyword(s):  
Emission Spectra ◽  
Infrared Emission

Temperature Gradients Through EHD Films and Molecular Alignment Evidenced By Infrared Spectroscopy

1981 ◽  
Vol 103 (1) ◽  
pp. 65-73 ◽  
Author(s):  
V. W. King ◽  
J. L. Lauer
Keyword(s):  
Absorption Spectrum ◽  
Emission Spectra ◽  
Infrared Emission ◽  
Molecular Alignment ◽  
Temperature Gradients ◽  
Spectral Change ◽  
Continuum Source ◽  
Polyphenyl Ether ◽  
Elementary Analysis ◽  
Gap Width

Partial and complete emission band reversals have been observed in the infrared emission spectra from portions of operating sliding contacts. An elementary analysis has been carried out to show that partial reversals are due to temperature gradients in the fluid film—the film acts both as a radiation-emitter and absorber, and that total reversals—an emission spectrum appears as an absorption spectrum—are likely to be due to a continuum source, such as hot solid asperities. The total energy radiated under the latter conditions exceeds that under the others. A decrease in gap width with increased load was accompanied by a dramatic spectral change in the case of 5P4E polyphenyl ether, which is indicative of molecular alignment.

Pre-Excitation, Catalytic Oxidation of Analytes over Hopcalite in Flame/Furnace Infrared Emission (FIRE) Spectrometry

1992 ◽  
Vol 46 (4) ◽  
pp. 631-639 ◽  
Author(s):  
Yunke Zhang ◽  
Marianna A. Busch ◽  
Kenneth W. Busch
Keyword(s):  
Detection Limit ◽  
Soot Formation ◽  
Vibrational Excitation ◽  
Infrared Emission ◽  
Optimum Operating ◽  
Air Flow Rate ◽  
Linear Calibration ◽  
Furnace Temperature ◽  
Optimum Operating Temperature ◽  
Pure Acetone

Gas-phase infrared emission measurements made with the use of a new, specially designed, electrically heated furnace or a small hydrogen/air flame have shown that oxidation of a variety of carbon-based analytes to CO2 over the catalyst hopcalite prior to vibrational excitation in the furnace or flame markedly improves the response of the FIRE radiometer. Calibration curves obtained with the use of the furnace alone were generally nonlinear, while those obtained with the flame alone had slopes that were compound dependent. By the use of hopcalite in conjunction with the furnace, conversion to CO2 was significantly improved, and the FIRE response to pure acetone, benzene, dichloromethane, 1-chloro-2-methylpropane, heptane, methanol, and toluene became directly proportional to the number of moles of carbon introduced. In the case of the flame, as little as 0.1 g of hopcalite was sufficient to give a single, linear calibration curve (based on moles of carbon) for injection volumes of 0.2–1.0 μL of a test mixture composed of equal volumes of acetone, benzene, hexane, propanol, and tetrahydrofuran. With the use of hopcalite at its experimentally determined, optimum operating temperature of 380°C, an air flow rate of 45 mL min−1, and a furnace temperature of 600°C, the detection limit for hexane was found to be 518 ng C s−1. The use of hopcalite in conjunction with the flame (900°C) improved this detection limit by two orders of magnitude, due to the combined effects of an increase in excitation temperature and a decrease in source background noise. Injection of chlorinated compounds was found to temporarily poison the hopcalite, resulting in soot formation and loss of catalytic activity for periods of approximately ten minutes.

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