大气环境下氩气空心针-板放电中OH和O的空间分布

Spatial Distributions of OH Radicals and O Atoms in Argon Hollow Needle-Plate Discharge in Ambient Air

研究了大气环境下氩气空心针-板放电等离子体中OH和O的空间分布。利用空心针-板放电装置,得到了3cm长的等离子体炬。首先采集了300～800nm范围内的光发射谱,发现除了ArⅠ谱线、N2第二正带系谱线C3Πu(ν′=0)→B3Πg(ν″=0)外,还出现了OH自由基的谱带、OⅠ谱线和较弱的H谱线。由于含氧活性粒子在材料表面改性中具有重要作用,实验选取了OH发射的309nm附近的谱带和激发态O发射的777.4nm谱线,分析了它们的相对强度,得到了粒子的空间分布。结果表明:沿等离子体从弧根到弧梢位置,OH自由基数量迅速减少,O原子数量呈现先增多后减少的规律。

In the present work,the spatial distributions of OH radicals and O atoms were studied in argon hollowneedle-plate discharge in ambient air.A 3 cm long plasma torch was generated in the discharge.The optical emission spectrum from 300 to 800 nm was collected.Besides ArⅠ lines and N2 second positive band system,OH emission band around 309 nm,O line at 777.4 nm and weaker H line were found in the optical emission spectrum.Because OH radicals and O atoms play an important role in material surface modification,the relative intensities of the OH radicals band （around 309 nm） and O atom line （777.4 nm） were analyzed.The results show that the number of OH radicals decreases rapidly and the number of O atoms follows a rule of increasing firstly and then decreasing from arc root to arc tip.