介质势垒放电(DBD)等离子体中NO荧光发射谱研究

The Fluorescence Emission Spectrum of NO in Dielectric Barrier Discharge (DBD) Plasma

利用介质阻挡放电 (DBD)等离子体技术对大气污染物NO分子进行了光谱研究 ,得到了低气压条件下放电等离子体在 2 1 0～ 2 80nm光谱范围内的荧光发射谱。该谱明显的表现为双峰结构 ,谱线均成对出现 ,强度分布符合Frank Condon原理 ,且最大峰值位置出现在 2 36nm处 ,将该组谱线归属为NO分子的A2 ΣA+→X2 Π1 / 2 ,2 / 3 跃迁。荧光产生过程为 :基态NO分子与高能电子发生非弹性碰撞被激发至激发态A2 Σ+ 后自发跃迁回基态同时辐射出荧光。通过测量等离子体中NO分子和N2 分子 337nm谱线强度随时间的变化关系 ,初步证实了放电等离子体中存在的NO分子的分解机制为 :e +NO→N +O +e,N +NO→N2 +O ,O +NO→NO2+hν。

Dielectric barrier discharge was used to study the NO molecules of the atmophere pollution, and the fluorescence emission spectrum in the range of 210-280 nm at low pressure was obtained in this plasma. The spectrum shows obviously the structure of double apices, whose intensity distribution in accord with Frank-Condon principle and the maximum lies at 236 nm. The main lines are attributed to the A (2)Sigma(+) -->X (2)Pi(1/2,2/3) transition. The produce of fluorescence can be described as: NO molecules at the ground state are impacted to the A (2)Sigma(+) excited state by fast electrons, and then transit to the ground state radiating fluorescence. By measuring the relation between discharge time and emission intensity of NO and N-2 molecules in the discharge plasma, we demonstrated the dissociation mechanism of NO in the discharge period, which can be interpreted as: e* + NO-->N + O + e, N + NO-N-2 + 0, 0 + NO-->NO2 + hnu.