Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA.
J Phys Chem A. 2010 Jan 28;114(3):1529-38. doi: 10.1021/jp907885d.
Infrared action spectroscopy is utilized to characterize the gas-phase, hydrogen-bonded H(2)O-HO complex, a primary interaction in the hydration of the hydroxyl radical. The OH radical stretch of the H(2)O-HO complex is identified at 3490 cm(-1), shifted 78 cm(-1) to lower frequency of the OH monomer transition. The stability of the complex, D(0) < or = 5.14 kcal mol(-1), is derived from the highest observed OH product channel in the associated product state distribution. The assignment is supported by high level ab initio calculations of the spectral shift of the binary complex from free OH and its dissociation energy, D(e)(CBS-infinity) = 5.6 kcal mol(-1). A second weaker feature, appearing 15 cm(-1) to lower frequency at 3475 cm(-1), is attributed to a hot band, the OH radical stretch originating from an out-of-plane H(2)O bending state, based on two-dimensional calculations of frequencies and strengths of transitions involving the coupled vibrational modes.
利用红外作用光谱学来描述气相氢键合的 H(2)O-HO 复合物，这是羟基自由基水合作用的主要相互作用。H(2)O-HO 复合物的 OH 自由基伸缩振动在 3490 cm(-1)处被识别，向低频率移动了 78 cm(-1)，低于 OH 单体跃迁的频率。复合物的稳定性 D(0) < or = 5.14 kcal mol(-1)，是通过在相关产物状态分布中观察到的最高 OH 产物通道得出的。该分配得到了高水平从头算计算的支持，这些计算对二元复合物的光谱位移和其离解能 D(e)(CBS-无穷大) = 5.6 kcal mol(-1)进行了研究。第二个较弱的特征出现在 3475 cm(-1)处，频率低 15 cm(-1)，归因于一个热带，即 OH 自由基伸缩振动源自平面外 H(2)O 弯曲态，这是基于涉及耦合振动模式的二维计算得出的。
