Ultrafast Dynamics of Polar Monosubstituted Benzene Liquids Studied by the Femtosecond Optical Kerr Effect
Ultrafast Dynamics of Polar Monosubstituted Benzene Liquids Studied by the Femtosecond Optical Kerr Effect
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飞秒光学克尔效应研究极性单取代苯液体的超快动力学
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
S. Meech
中科院分区：
文献类型：
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作者：
N. Smith;S. Meech
通过测量光学外差探测到的光学克尔效应，记录了液体苯胺、硝基苯和苯腈的飞秒和皮秒动力学。亚皮秒动力学的一个主要部分是振颤运动。对不同转动惯量的对位取代苯腈衍生物的研究支持了这一任务。三种液体的振动频率与温度的关系很弱，但在惰性溶剂中稀释时振动频率向低频率移动。皮秒弛豫动力学可用双指数函数很好地描述。最慢的松弛时间表现为，至少在定性上，正如定向扩散的流体动力学模型所预测的那样。然而，定量分析表明，一些关于分子形状或流体动力学边界条件的假设不足以完全描述这些液体中的扩散定向运动。作为函数的最慢松弛时间的测量。
The femtosecond and picosecond dynamics of liquid aniline, nitrobenzene, and benzonitrile have been recorded through measurements of the optically heterodyne detected optical Kerr effect. A major part of the subpicosecond dynamics is assigned to librational motion. This assignment is supported by studies of para-substituted benzonitrile derivatives with differing moments of inertia. The librational frequencies of the three liquids are only weakly dependent on temperature but shift to lower frequency on dilution in inert solvents. The picosecond relaxation dynamics are well described by a biexponential function. The slowest relaxation time behaves, at least qualitatively, as predicted by hydrodynamic models of orientational diffusion. However, quantitative analysis suggests that some of the assumptions concerning the molecular shape or hydrodynamic boundary condition are inadequate to completely describe diffusive orientational motion in these liquids. Measurements of the slowest relaxation time as a funct...