Steric Effect in the Energy Transfer Reaction of Oriented CO (a 3Π, v′ = 0, Ω = 1 and 2) + NO (X 2Π) → NO (A 2Σ+, B 2Π) + CO (X 1Σ+)
Steric Effect in the Energy Transfer Reaction of Oriented CO (a 3Π, v′ = 0, Ω = 1 and 2) + NO (X 2Π) → NO (A 2Σ+, B 2Π) + CO (X 1Σ+)
复制标题
定向CO (a 3Π, v′ = 0, Ω = 1 and 2) + NO (X 2Π) → NO (A 2Σ+, B 2Π) + CO (X 1Σ+) 能量转移反应中的空间效应
DOI：
10.1021/jp202781g
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发表时间：
2011
期刊：
影响因子：
2.9
通讯作者：
Y. Matsuura
中科院分区：
文献类型：
--
作者：
H. Ohoyama;Y. Matsuura
用电六极杆制备了取向CO（a3 <$，v '= 0，Ω = 1，2）束，并将其应用于CO（a3 <$，v'= 0，Ω = 1，2）+ NO（X2 <$）→ NO（A2 <$+，B2 <$）+ CO（X1 <$+）的能量转移反应.测量了NO（A_2 ~+，B_2 ~+）在三种取向构型（C端，O端，无规）下的发射光谱。发射光谱的形状（和/或内部激发的产品）原来是不敏感的分子取向。NO（A2 <$+，v′ = 0-2）和NO（B2 <$+，v′ = 0-2）的振动分布分别为Nv ′=0：Nv′=1：Nv′=2= 1：0.40 ± 0.05：0.10 ± 0.05和Nv ′=0：Nv′=1：Nv′= 2= 1：0.6 ± 0.1：0.7 ± 0.1，分支比γ/β [=NO（A2 <$+）/NO（B2 <$+）]为γ/β = 0.3 ± 0.1。NO（A，B）的这些振动分布本质上是CO（X，v″）与NO（A2 <$+，v′ = 0-2）、NO（B2 <$，v ′ = 0-2）在能量传递过程中，由于CO（a3 <$，v′ = 0）→ CO（X，v″）垂直跃迁产生的CO（X，v ″）振动分布的能量限制而产生的产物对关联。在220 < λ < 290 nm [NO（A → X）占优势]和320 < λ < 400 nm [NO（B → X）占优势]两个波长区测定了位阻不透明度函数。对于两个通道NO（A2 <$+，B2 <$+），一个显着的CO（a3 <$+）的对齐效果是公认的，最大的反应性，在分子轴方向上的反应性较小的横向方向观察。这些CO（α 3 Π）排列效应主要归因于[CO（2π）+ NO（6σ（2π））]和[CO（5σ）+NO（1π（2π））]两组分子轨道重叠上的空间不对称性。所有的实验观察支持的电子交换机制，是通过形成一个弱结合的复合物OCNO操作。
The oriented CO (a3Π, v′ = 0, Ω = 1 and 2) beam has been prepared by using an electric hexapole and applied to the energy transfer reaction of CO (a3Π, v′ = 0, Ω = 1 and 2) + NO (X2Π) → NO (A2Σ+, B2Π) + CO (X1Σ+). The emission spectra of NO (A2Σ+, B2Π) have been measured at three orientation configurations (C-end, O-end, random). The shape of the emission spectra (and/or the internal excitation of products) turns out to be insensitive to the molecular orientation. The vibrational distributions of NO (A2Σ+, v′ = 0–2) and NO (B2Π, v′ = 0–2) are determined to beNv′=0:Nv′=1:Nv′=2= 1:0.40 ± 0.05:0.10 ± 0.05 andNv′=0:Nv′=1:Nv′= 2= 1:0.6 ± 0.1:0.7 ± 0.1, respectively, and the branching ratio γ/β [=NO (A2Σ+)/NO (B2Π)] is estimated to be γ/β ∼ 0.3 ± 0.1 by means of spectral simulation. These vibrational distributions of NO (A, B) can be essentially attributed to the product-pair correlations between CO (X, v″) and NO (A2Σ+, v′ = 0–2), NO (B2Π, v′ = 0–2) due to energetic restriction under the vibrational distribution of CO (X, v″) produced from the vertical transition of CO (a3Π, v′ = 0) → CO (X, v″) in the course of energy transfer. The steric opacity function has been determined at two wavelength regions: 220 < λ < 290 nm [NO (A → X) is dominant]; 320 < λ < 400 nm [NO (B → X) is dominant]. For both channels NO (A2Σ+, B2Π), a significant CO (a3Π) alignment effect is recognized; the largest reactivity at the sideways direction with the small reactivity at the molecular axis direction is observed. These CO (a3Π) alignment effects can be essentially attributed to the steric asymmetry on two sets of molecular orbital overlap, [CO (2π) + NO (6σ (2π))] and [CO (5σ)+NO (1π (2π))]. All experimental observations support the electron exchange mechanism that is operative through the formation of a weakly bound complex OCNO.