研究钠氩(Na-Ar)混合物电离后产生的原子发射光谱的时间分辨特性。氩763.5 nm光谱强度随时间演变出现2个峰,第1个峰的衰减时间为(33.3±2.3) ns,激发态钠通过碰撞传能[(时间常数为(15.2±0.8) ns]将氩激发到2p6能级,再由该能级的粒子快速辐射形成第1个峰;第2个峰由氩离子与电子复合产生,其衰减过程包括快过程[(0.24±0.03) μs]和慢过程[(3.98±1.03) μs]。利用电子浓度随时间的演变关系分析了复合过程对衰减时间的影响机理,获得了电子浓度、电子温度随时间的演变关系。利用时间分辨光谱解释了钠双线辐射加宽差异的假象,其成因是Stark加宽后的氩588.9 nm谱线叠加在钠D2线上以及钠双线的自吸收。复合后,激发态氩原子的能级间隔较小,经过级联弛豫后,2p6能级粒子数的积累时间比钠3P能级更短,氩原子发射谱线的持续时间明显短于钠原子。

Herein, the atomic emission spectrum of a sodium-argon mixture is obtained after ionization, and its time-resolved characteristics are experimentally studied. When observing the time-resolved evolution of argon spectral intensity at 763.5 nm, two peaks appear. The first peak with a decay time of (33.3±2.3) ns is observed via the fast radiation of particles at argon 2p6 state, which excited through collisional energy transfer from the excited sodium atom [time constant is (15.2±0.8) ns]. Following the recombination of argon ions and electrons, the second peak is observed; this peak''s decay process contains both a fast [(0.24±0.03) μs] and a slow [(3.98±1.03) μs] steps. Using the evolution relationship of electron density with time, the mechanism for decay time, which is impacted by the recombination process, is analyzed. The evolution relationships of electron density and electron temperature with time are obtained. The time-resolved atomic emission spectrum can experimentally explain the unusual phenomenon of the obviously different broadening between the D1 and D2 lines of the sodium spectra; these reasons are the spectral line of argon at 588.9 nm overlaying the sodium D2 line (589.0 nm) after Stark broadening and the self-absorption on two D lines of the sodium. Because the energy level splitting is small for the excited argon atom after recombination, the particle population accumulated on the 2p6 state via cascade relaxation takes a shorter time than that on the sodium 3P state, and the duration of the argon atom emission spectrum is obviously shorter than that of the sodium atom.