Reinvestigation of the spectroscopy of the (A)over-tilde(3)Pi(u)-(X)over-tilde(3)Sigma(-)(g) transition of the NCN radical at high temperature: Application to quantitative NCN measurement in flames
Reinvestigation of the spectroscopy of the (A)over-tilde(3)Pi(u)-(X)over-tilde(3)Sigma(-)(g) transition of the NCN radical at high temperature: Application to quantitative NCN measurement in flames
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高温下 NCN 自由基 (A)over-tilde(3)Pi(u)-(X)over-tilde(3)Sigma(-)(g) 跃迁光谱的重新研究：在定量 NCN 测量中的应用
DOI：
10.1016/j.combustflame.2012.12.009
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发表时间：
2013
影响因子：
4.4
通讯作者：
P. Desgroux
中科院分区：
文献类型：
--
作者：
N. Lamoureux;C. Western;X. Mercier;P. Desgroux
在火焰中，NCN-NO机理的引发反应（CH+N2=NCN+H）涉及NCN自由基。这种自由基是一种非常小的物种，在烃/空气火焰中的摩尔分数仅达到几百ppb，这使得其绝对浓度分布的实验测定具有挑战性。本研究的目的是（1）表明，明确的分配的NCN自由基的吸收光谱线，可以在选定的火焰和（2）提供的温度依赖的NCN吸收截面需要确定的绝对NCN浓度。在这项工作中，NCN光谱的A-X带是完全重新使用理论光谱计算。的光谱常数的评估是基于比较的理论光谱，模拟与pgopher程序，在低压乙炔/氧气/氮气火焰中获得的扩展LIF光谱。从计算的电子跃迁矩和配分函数出发，计算了NCN在最强带头波长（329.13nm）处随温度变化的吸收截面σ（T）。横截面温度依赖性与Dammeier和Friedrichs [J. Phys. Chem. A 114（2010）12963]在激波管中使用NCN 3热解然后进行单程NCN吸收测量实验获得的结果非常一致，尽管它们的值相差2.6倍。本文提供了在高温火焰中用CRDS获得的NCN在329.0 - 329.3nm之间的第一个吸收光谱，从中可以清楚地识别出带头。已检查了可能的干扰的发生。最后，通过重新考虑以前发表的数据和增加一个新的数据，给出了CRDS在三个低压预混火焰中得到的峰值摩尔分数。该测定所需的实验吸收截面来自理论吸收截面，同时考虑到激光带宽。NCN测量的准确性进行了讨论，并强调耦合CRDS和LIF的好处。
The initiation reaction of the prompt-NO mechanism in flames (CH+N2=NCN+H) involves the NCN radical. This radical is a very minor species reaching only a few hundreds of ppb in mole fraction in hydrocarbon/air flames, which makes the experimental determination of its absolute concentration profile challenging. The aim of this study is (1) to show that unambiguous assignment of absorption spectral lines of the NCN radical can be obtained in selected flames and (2) to provide the temperature-dependent NCN absorption cross sections needed to determine the absolute NCN concentration. In this work, NCN spectroscopy of the A–X band is fully revisited using theoretical spectroscopic calculations. Assessment of the spectroscopic constants is based on comparison of the theoretical spectrum, simulated with the pgopher program, with an extended LIF spectrum obtained in a low-pressure acetylene/oxygen/nitrogen flame. From the calculated electronic transition moments and the partition function, the temperature-dependent absorption cross section of NCN σ(T) has been calculated at the most intense bandhead wavelength (329.13nm). Cross-section temperature dependence is in very good agreement with that experimentally obtained by Dammeier and Friedrichs [J. Phys. Chem. A 114 (2010) 12963] using NCN3pyrolysis in a shock tube followed by single-pass NCN absorption measurement, though their values differ by a factor of 2.6. The first NCN absorption spectrum between 329.0 and 329.3nm obtained by CRDS at high temperature in a flame is provided here, from which the bandhead is clearly identified. Occurrence of possible interferences has been examined. Finally, peak mole fractions obtained by CRDS are given in three low-pressure premixed flames by reconsidering previous published data and adding a new datum. The experimental absorption cross section required for this determination is derived from the theoretical one, taking into account the laser bandwidth. The accuracy of the NCN measurements is discussed and highlights the benefit of coupling CRDS and LIF.
NCN(3)作为高温NCN自由基源的热分解：NCN((3)Σ)的单重态-三重态弛豫和吸收截面
DOI：
10.1021/jp1043046
发表时间：
2010
期刊：
The journal of physical chemistry. A
影响因子：
--
作者：
J. Dammeier;G. Friedrichs
通讯作者：
G. Friedrichs
直接测量 NCN O、NCN NCN 和 NCN M 反应的高温速率常数
DOI：
10.1039/c1cp22123j
发表时间：
2012
期刊：
Physical chemistry chemical physics : PCCP
影响因子：
--
作者：
J. Dammeier;N. Faßheber;G. Friedrichs
通讯作者：
G. Friedrichs