Electronic Population Inversion in HCCO/DCCO Products from Hyperthermal Collisions of O(3P) with HCCH/DCCD
Electronic Population Inversion in HCCO/DCCO Products from Hyperthermal Collisions of O(3P) with HCCH/DCCD
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DOI：
10.1021/jz400568t
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发表时间：
2013-04-18
影响因子：
5.7
通讯作者：
Minton, Timothy K.
中科院分区：
文献类型：
--
作者：
Lahankar, Sridhar A.;Zhang, Jianming;Minton, Timothy K.
用交叉分子束技术研究了O（P-3）与乙炔的超高温反应动力学，采用质谱和光学检测产物。O（P-3）+ HCCH/DCCD → HCCO/DCCO + H/D在碰撞能为40-150 kcal mol ~（-1）时，可通过多种途径生成基态双重态或电子激发四重态和双重态的烯酮自由基（HCCO或DCCO）。理论计算支持各种反应途径的分配。电子激发的部分是相当大的。在研究的最高碰撞能量下，类似于65%的存活的烯酮基自由基产物是电子激发的，其中大多数激发产物处于四重态。在这种情况下，粒子数反转存在于烯酮产物的电子激发四重态和基态双重态之间。在双分子反应中，这种显著的电子激发是不寻常的，特别是当基态产物可以通过自旋允许的途径到达时。
The dynamics of hyperthermal O(P-3) reactions with acetylene have been investigated with the use of crossed molecular beams techniques, employing both mass spectrometric and optical detection of products. With collision energies of 40-150 kcal mol(-1), O(P-3) + HCCH/DCCD -> HCCO/DCCO + H/D may follow multiple pathways to form the ketenyl radical (HCCO or DCCO) in ground doublet states or in electronically excited quartet and doublet states. Theoretical calculations support the assignment of the various reaction pathways. The fraction of electronic excitation is substantial. At the highest collision energy studied, similar to 65% of the ketenyl radical products that survive are electronically excited, with the majority of the excited products in a quartet state. In this case, a population inversion exists between the electronically excited quartet and ground doublet states of the ketenyl product. Such significant electronic excitation in products is unusual in bimolecular reactions, especially when ground-state products are accessible by spin-allowed pathways.