Rb-H₂(N₂)系统中的振动碰撞能量弛豫

Experimental Evaluation of Vibrational Relaxation Energy Transfer in Rb-H₂(N₂) Mixture

摘要: 激光激发Rb原子至高位振动态，与H₂反应生成RbH (X¹Σ+，v" = 0)分子。利用简并受激超拉曼泵浦激发RbH (X¹Σ+ v" = 17~20)高位振动态。实验研究高位振动态RbH分子与H₂(N₂)的碰撞弛豫传能过程。利用时间分辨荧光光谱得到RbH (X¹Σ+ v" = 17~20)的弛豫率，测量不同气压下各振动能级有效寿命，由Stern- Volmer公式得到RbH分子v" = 17~20与H₂的碰撞弛豫速率系数。充入不同配比的N₂和H₂混合气体，由类似方法计算了RbH (X¹Σ+ v" = 17~20)与N₂的碰撞弛豫速率系数。由LIF光强随探测延迟时间的演化关系给出了RbH与H₂碰撞v" = 17→10和RbH与N₂碰撞v" = 20→15的多量子弛豫实验证据。

Abstract: Rb-H₂ mixture was irradiated with pulses of 420.4nm radiation from a DYE laser. The vibrational levels of RbH(Х¹Σ+ v" = 0 - 2) generated in the reaction of Rb(6P) and H₂. Highly vibrationally excited RbH(X¹Σ+ v" = 17 - 20) were prepared using degenerate stimulated hyper-Raman pumping. An experimental study of vibrational relaxation energy transfer in RbH(X¹Σ+ v" = 17 - 20)-H₂(N₂) collisions and their vibrational relaxation rate coefficients had been performed. A CW laser was used to probe the prepared vibrational state. The decay signal of laser induced time-resolved flu-orescence from A¹Σ+(v')→Х¹Σ+(v") transition was monitored. Based on the Stern-Volmer equation, the total relaxation rate coefficient kv"(H₂) had been yielded. The total pressure of H₂-N₂ mixture was constant and the α(mole fraction N₂) changed. The values of kv"(N₂) were obtained in a similar method. The direct experimental evidence of multiquantum relaxation was prepared by time pro-files of relative intensity of RbH v" = 17, 20. The initial population for RbH (v" = 17, 20) was relaxed to much lower vibrational levels (Δv = −7 and Δv= −5).