Transient grating study of the intermolecular dynamics of liquid nitrobenzene
Transient grating study of the intermolecular dynamics of liquid nitrobenzene
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DOI：
10.1088/1674-1056/25/10/107802
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发表时间：
2016-08
影响因子：
1.7
通讯作者：
Honglin Wu;Yunfei Song;Guoyang Yu;Yanqiang Yang
中科院分区：
文献类型：
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作者：
Honglin Wu;Yunfei Song;Guoyang Yu;Yanqiang Yang
采用飞秒时间分辨瞬态光栅（TG）技术研究了液相分子间动力学。两个交叉激光脉冲对样品的非共振激发产生瞬态克尔光栅，通过监测第三个延时探针脉冲的衍射可以检测液体的分子运动。在液体硝基苯（NB）中，观察到三个分子间过程，其寿命分别为37.9±1.4 ps, 3.28±0.11 ps和0.44±0.03 ps。这些弛豫分别与分子定向扩散、偶极子/诱导偶极子相互作用和液笼中的振动有关。此结果与测量中间过程寿命为1.9 ps的OKE实验略有不同。电场对物质的影响在TG和光学Kerr效应（OKE）实验中是不同的，这应该是导致这两类实验结果不同的原因。本研究表明TG技术在分子间动力学研究中是一种有用的替代方法。
Femtosecond time-resolved transient grating (TG) technique is used to study the intermolecular dynamics in liquid phase. Non-resonant excitation of the sample by two crossing laser pulses results in a transient Kerr grating, and the molecular motion of liquid can be detected by monitoring the diffraction of a third time-delayed probe pulse. In liquid nitrobenzene (NB), three intermolecular processes are observed with lifetimes of 37.9±1.4 ps, 3.28±0.11 ps, and 0.44±0.03 ps, respectively. These relaxations are assigned to molecular orientational diffusion, dipole/induced dipole interaction, and libration in liquid cage, respectively. Such a result is slightly different from that obtained from OKE experiment in which the lifetime of the intermediate process is measured to be 1.9 ps. The effects of electric field on matter are different in TG and optical Kerr effect (OKE) experiments, which should be responsible for the difference between the results of these two types of experiments. The present work demonstrates that TG technique is a useful alternative in the study of intermolecular dynamics.