用发射光谱法测量氮气直流辉光放电的转动温度

本文报道了氮气气压分别为10和20Pa时，对直流辉光放电的发射光谱进行测量和分析的结果。选择的研究对象为N2放电中形成的N2^ B^2∑u^ →X^2∑g^ 跃迁的Δv=v′-v″=0谱带系中v′=0→v″=0谱带的R支。在阴极背面辉光区、阴极鞘层区、正柱区以及阳极辉光区中分别选择一点进行了转动分辨的发射光谱的测量。利用自己编写的光谱拟合程序，获得了相应的实验条件下N2^ 的转动温度，给出了转动温度随放电电压的变化趋势，其结果可以用直流放电的帕邢定律得到很好的解释。在10和20Pa气压下，放电的阴极鞘层区、正柱区、阳极辉光区中的转动温度都随放电电压呈现出了不同的变化趋势，甚至是完全相反的变化趋势。我们认为这是由于气压不同时，放电状态不同所致：气压为10Pa时的放电是正常辉光放电，而气压为时20Pa的放电为反常辉光放电。

Measurement of Rotational Temperature in N2 DC Glow Discharge by Optical Emission Spectroscopy

Measurements of rotational temperature as low as several hundred Kelvin have been achieved using optical emission spectroscopy (OES) in nitrogen DC glow discharge. The strongest band of the first negative system of nitrogen molecule ion was chosen to determine the rotational temperature of nitrogen DC glow discharge at 4 different positions in the discharge area: back of the cathode; cathode sheath; positive column and anode glow region. In positive column the rotational temperature of N + 2 increases apparently with the increasing discharge voltage from 500-1 100 V when the pressure is 10 Pa. However at pressure of 20 Pa the rotational temperature in positive column increases slightly with the increase of discharge voltage. On the contrary, the rotational temperature in cathode sheath takes reverse tendency when the discharge voltage varies from 500-1 100 V. As regard the anode glow region, the rotational temperature at 10 Pa decreases with the increase of discharge voltage, but that at the 20 Pa increases. We attribute the different changing tendencies of the rotational temperature to the different discharge status at different pressure. When the discharge voltage varies from 500 to 1 100 V, the discharge at pressure of 10 Pa is normal glow and that at 20 Pa is abnormal glow.