氮分子对激发态氩原子的淬灭效应

Quenching Effect of Nitrogen Molecule to Argon Atom in Excited State

在利用发射光谱方法进行电子激发温度测量中,由于N2分子对掺杂原子的淬灭作用,使得计算结果与实际结论有所区别,所以,有必要研究这种淬灭作用,以修正淬灭影响.本文采用发射光谱方法,在标准大气压下,对N2/Ar混合气体负脉冲流光放电激励下氮分子对激发态氩原子的淬灭过程进行了实验研究.其淬灭机理就是处于激发电子态的氩原子与基态的氮分子发生近共振能量转移碰撞,处于激发电子态的氩原子将其激发能传递给氮分子而产生淬灭效应.实验表明:激发态氩原子能级高度所对应氮分子激发电子态的转动能级能量间隔越小,淬灭效应越明显;淬灭率随氮气含量的增大而增大,且最终趋近于某一定值;放电注入功率也对淬灭率有影响,淬灭率随着注入功率的增大而减弱,且最终亦趋近于某一定值,其原因主要是放电等离子体区气体温度会随注入功率增大而有所升高,导致气体密度降低,故淬灭作用会有所降低.

In the measurement of electronic excitation temperature using the emission spectroscopy,it has difference between the measure result and the actual behavior because of the quenching influence of nitrogen molecule to doped atom.Therefore,it is necessary to study the quenching coefficient to correct the quenching influence.At normal atmospheric pressure,the quenching process of nitrogen molecule to excited argon atom was investigated under the negative pulse streamer excitation of argon/nitrogen mixture by emission spectroscopy.The quenching mechanism was described that argon atom in excited state transfer its excited energy to nitrogen molecule in ground state on near resonance collision process between excited state argon atom and nitrogen molecule.Quenching efficiency depended on relative position of energy level,the ratio of mixture and discharge injection power.The results indicated that the quenching efficiency became much visibler with the smaller distance between the rotation energy level of nitrogen molecule and energy level of excited argon atom.Additionally,the quenching efficiency would increase and reach a certain value finally when the nitrogen proportion in mixture increased and the injection power decreased.