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EXPRESS: Atomic and Molecular Species Post-2 μs Dynamics in Laser-Induced Carbon Plasmas in Air
Applied Spectroscopy ( IF 3.5 ) Pub Date : 2020-11-10 , DOI: 10.1177/0003702820971602
Houssyen Yousfi 1, 2 , Samira Abdelli-Messaci 2 , Ourida Ouamerali 1 , Azeddine Dekhira 1
Affiliation  

Laser-induced carbon plasma in air undergoes various physicochemical processes that affect the kinetic chemistry of species of the plasma plume. We report the time- and space- resolved characterization of carbon plasma produced by infrared nanosecond laser into air at atmospheric pressure. Investigating the laser fluence effect highlights dissociation for fluences > 40 J cm-2, and recombination processes in the fluence range of 10-40 J cm-2. Emission intensities of C2 and CN molecules undergo an enhancement at specific spatiotemporal locations in the laser-induced plasma. At a value of 27 J/cm2 and 0.8 mm from the plasma ignition, molecular band formation is favored for the specific temperature and density values of 1.7E15 cm-3 and 9502 K. The vibrational temperatures of molecules are determined using non-linear spectral data fitting program. The shock front between laser-induced carbon plasma and air may lead to a significant shock wave that affects the occurrence of molecular CN and C2 formation. This can be explained by the distinct temperatures exhibited by CN and C2 molecules with laser fluence. The atomic carbon travels farther to react and form C2, where the ionization-recombination process plays a significant role in its formation. Collisions of C with N neutrals and N2 molecules are the plausible origin of CN generation. Moreover, the density of CN in the plasma depends on C2 molecules.

中文翻译:

EXPRESS:空气中激光诱导碳等离子体中的原子和分子物种后 2 μs 动力学

空气中的激光诱导碳等离子体经历各种物理化学过程,这些过程会影响等离子体羽流物种的动力学化学。我们报告了由红外纳秒激光在大气压力下产生的碳等离子体的时间和空间分辨特性。研究激光能量密度效应突出了能量密度 > 40 J cm-2 的解离,以及能量密度范围为 10-40 J cm-2 的重组过程。C2 和 CN 分子的发射强度在激光诱导等离子体中的特定时空位置发生增强。在 27 J/cm2 的值和距离等离子点火 0.8 mm 处,分子带形成有利于特定温度和密度值 1.7E15 cm-3 和 9502 K。分子的振动温度是使用非线性光谱确定的数据拟合程序。激光诱导碳等离子体与空气之间的激波前沿可能会产生显着的激波,影响分子 CN 和 C2 形成的发生。这可以通过 CN 和 C2 分子在激光能量密度下表现出的不同温度来解释。原子碳走得更远以进行反应并形成 C2,其中电离 - 复合过程在其形成中起着重要作用。C 与 N 中性粒子和 N2 分子的碰撞是 CN 生成的合理起源。此外,等离子体中 CN 的密度取决于 C2 分子。原子碳移动得更远以进行反应并形成 C2,其中电离 - 复合过程在其形成中起着重要作用。C 与 N 中性粒子和 N2 分子的碰撞是 CN 生成的合理起源。此外,等离子体中 CN 的密度取决于 C2 分子。原子碳移动得更远以进行反应并形成 C2,其中电离 - 复合过程在其形成中起着重要作用。C 与 N 中性粒子和 N2 分子的碰撞是 CN 生成的合理起源。此外,等离子体中 CN 的密度取决于 C2 分子。
更新日期:2020-11-10
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