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Intermolecular Vibrational Energy Transfers in Melts and Solutions
Yu-neng Shen1,2, Bo Jiang3, Chuan-qi Ge1,4, Gang-hua Deng1, Hai-long Chen3, Xue-ming Yang1, Kai-jun Yuan1, Jun-rong Zheng3
1.State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China;2.University of the Chinese Academy of Sciences, Beijing 100049, China;3.Department of Chemistry, Rice University, Houston, Texas, USA;4.School of Physics and Electronic Technology, Liaoning Normal University, Dalian 116029, China
Abstract:
Resonant and nonresonant intermolecular vibrational energy transfers in Gdm-SCN/KSCN=1/1, GdmSCN/KS13CN=1/1 and GdmSCN/KS113C15N=1/1 mixed crystals in melts and in aqueous solutions are studied with the two dimensional infrared spectroscopy. The energy transfers in the samples are slower with a larger energy donor/acceptor gap, independent of the Raman spectra. The energy gap dependences of the nonresonant energy transfers cannot be described by the phonon compensation mechanism. Instead, the experimental energy gap dependences can be quantitatively described by the dephasing mechanism. Temperature dependences of resonant and nonresonant energy transfer rates in the melts are also consistent with the prediction of the dephasing mechanism. The series of results suggest that the dephasing mechanism can be dominant not only in solutions, but also in melts (pure liquids without solvents), only if the molecular motions (translations and rotations) are much faster than the nonresonant energy transfer processes.
Key words:  Vibrational energy transfers  2D IR  Phonon compensation mechanism  Dephasing mechanism
FundProject:This work was supported by the National Natural Science Foundation of China (No.21373213), the Chinese Academy of Sciences, and the Ministry of Science and Technology. Jun-rong Zheng is supported by the AFOSR Award No.FA9550-11-1-0070, the Welch foundation under Award No.C-1752, the David and Lucile Packard Foundation for a Packard fellowship, and the Alfred P. Sloan Foundation for a Sloan fellowship.
溶液和熔化状态下分子间的能量传递
沈宇能1,2, 蒋博3, 葛传琦1,4, 邓罡华1, 陈海龙3, 杨学明1, 袁开军1, 郑俊荣3
1.中国科学院大连化学物理研究所, 分子反应动力学国家重点实验室, 大连 116023;2.中国科学院大学, 北京 100049;3.莱斯大学化学系, 休斯顿;4.辽宁师范大学物理和电子工程系, 大连 116029
摘要:
通过二维红外光谱研究了GdmSCN/KSCN=1/1,GdmSCN/KS13CN=1/1和GdmSCN/KS13C15N=1/1三种混合晶体在熔融和溶液状态下的共振和非共振的分子间振动能量传递的性质. 在这些样品中,给体/受体的能量差越大,能量传递越慢. 而能量传递的快慢与拉曼光谱无关. 非共振能量传递与给体/受体的能量差的关系不能用声子补偿的机理来描述. 相反,它们的关系却可以用退相位机理来定量描述. 在熔融状态下,共振和非共振能量速率与温度的依赖关系也与退相位机理的预测相符合. 这一系列的结果表明只要分子的运动(平动和转动)远远快于非共振能量传递速率,那么退相位机理不仅在溶液中占主导,而且在熔融状态下(纯液体,不含溶剂)也占主导.
关键词:  振动能量传递  二维红外光谱  声子补偿机理  去相位机理
DOI:10.1063/1674-0068/29/cjcp1602028
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