Rate Coefficients for Vibrational Relaxation of OH(X^2Π, ν＝1-4) by He
Rate Coefficients for Vibrational Relaxation of OH(X^2Π, ν＝1-4) by He
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He 的 OH(X^2Π, ν=1-4) 振动弛豫速率系数
DOI：
10.1021/jp3114072
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
Nanase Kohno
中科院分区：
文献类型：
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作者：
戸田 聡;瀬川 勝盛;長田 重一;Nanase Kohno
OH（X2）与稀有气体碰撞产生的振动弛豫由于分子间的相互作用很小而非常缓慢。He对OH较低振动能级v ≤ 4的弛豫速率系数还没有测量，v = 2，<1 × 10 ~（-14）cm ~ 3分子~（-1）s ~（-1）的上限只有一个报道。本文研究了OH（X ~ 2）与He碰撞时，能级v = 1-4的振动弛豫。在266 nm波长下，以70-130 Torr的He为载气，对O3和H2的混合气体进行辐照，在O（1D）+ H2反应中产生OH（X ~ 2 = 0，v≤ 4）。通过A2 π +-X2Π跃迁，用激光诱导荧光（LIF）检测到OH的单振动能级。记录OH（v）的时间分辨LIF强度，并通过最初开发的积分轮廓法（IPM）进行动力学分析。在计算了扩散损失速率系数与压力的关系以及杂质对动力学的影响的基础上，（X2，v= 1-4）他已被确定为（2.9 ± 1.5）× 10-17，（1.4 ± 0.4）× 10-16，（5.2 ± 0.5）× 10-16，（1.6 ± 0.2）× 10- 15 cm 3 molecule-1 s-1（v = 1，2，3，4）（置信限为2σ）。速率系数在较高的振动水平较大，并顺利地与那些以前报道的forv= 10-12。
The vibrational relaxation of OH(X2Π) by collisions with rare gases is very slow due to small molecular interactions. No measurement of the rate coefficients has been made for relaxation of relatively low vibrational levelsv≤ 4 of OH by He, and there is only one report of the upper limit forv= 2, <1 × 10–14cm3molecule–1s–1. In this article, we have studied vibrational relaxation of the levelsv= 1–4 of OH(X2Π) by collisions with He. A gaseous mixture of O3and H2in a carrier gas at 70–130 Torr of He was irradiated at 266 nm, and OH(X2Π,v≤ 4) was generated in the reaction O(1D) + H2. A single vibrational level of OH was detected with laser-induced fluorescence (LIF) via the A2Σ+–X2Π transition. Time-resolved LIF intensities of OH(v) were recorded, and kinetic analysis was made by an originally developed integrated profiles method (IPM). On the basis of the evaluation of the pressure-dependent rate coefficients of diffusion loss and the effect of impurities on the kinetics, the rate coefficients of vibrational relaxation for OH(X2Π,v= 1–4) by He have been determined to be (2.9 ± 1.5) × 10–17, (1.4 ± 0.4) × 10–16, (5.2 ± 0.5) × 10–16, and (1.6 ± 0.2) × 10–15cm3molecule–1s–1forv= 1, 2, 3, and 4, respectively (the confidence limits are 2σ). The rate coefficients are larger at higher vibrational levels and smoothly correlate to those reported previously forv= 10–12.