光丝诱导大气等离子体化学反应生成的一氧化氮测量

Measurement of nitric oxide generated from filament-induced atmospheric chemical reaction

大气等离子体会诱导化学反应,一氧化氮(NO)是大气化学反应的主要产物之一,对其大气浓度的准确测量有助于揭示其大气化学反应机理并优化大气等离子体应用。在静态密闭反应池中,利用脉冲宽度35 fs、工作波长800 nm的脉冲激光生成光丝等离子体并诱导大气化学反应,进而采用中红外激光吸收光谱技术,实时测量了NO浓度随空气气压、反应时间的变化。在不同气压下,NO浓度随反应时间的增加而增加直至保持稳定,但NO达到稳定浓度所需要的反应时间随空气气压增加而延长。受到三体复合反应的影响,NO的累积体积比浓度从低气压时的400×10^(-6)以上减小到常压时(一个大气压)的120×10^(-6)左右。

Atmospheric plasma can induce chemical reactions,and nitric oxide(NO)is one of the main products of atmospheric chemical reactions.Accurate measurement of atmospheric concentration of NO is helpful for revealing the mechanism of atmospheric chemical reactions and optimizing the application of plasma in the atmospheric environment.In this work,NO is generated through atmospheric chemical reactions induced by filament plasma produced by ultrashort laser pulses with a pulse width of 35 femtoseconds and a working wavelength of 800 nm in a sealed absorption cell under variable air pressure.Then,mid-infrared laser absorption spectroscopy is used to measure NO in real time and in situ at variable pressure.It is found that under different air pressures,the concentration of NO produced increases with the reaction time until it remains stable.However,it requires more time for NO to reach a steady concentration with the increase of air pressure.Due to the influence of three-body recombination,the accumulated volume ratio concentration of NO decreases from more than 400×10^(-6) at low pressure to about 120×10^(-6) at atmospheric pressure.