Jen Myungsam, Lee Sebok, Jeon Kooknam, Hussain Shafqat, Pang Yoonsoo
Department of Chemistry and ‡Department of Physics and Photon Science, Gwangju Institute of Science and Technology , Gwangju 61005, Republic of Korea.
J Phys Chem B. 2017 Apr 27;121(16):4129-4136. doi: 10.1021/acs.jpcb.6b12408. Epub 2017 Apr 13.
We report time-resolved stimulated Raman spectra of alizarin in DMSO solution with 403 nm excitation. Upon photoexcitation, the intramolecular proton transfer reaction of alizarin occurs in 70-80 fs, which is confirmed by both the population growth and the frequency and bandwidth changes of skeletal vibrational modes of alizarin. Interestingly, the vibrational frequencies of ν(C═C) and ν(C═O) show opposite shifts during the reaction, which may implicate changes in the resonance structure of anthraquinone and the attached carbonyl group. Vibrational relaxation in the potential surface of the proton transferred tautomer of alizarin and the population decay occurring with two distinct time scales were also observed in addition to the solvation dynamics of DMSO solvent molecules.
我们报道了在403 nm激发下二甲基亚砜（DMSO）溶液中茜素的时间分辨受激拉曼光谱。光激发后，茜素的分子内质子转移反应在70 - 80飞秒内发生，这通过茜素骨架振动模式的布居增长以及频率和带宽变化得到证实。有趣的是，在反应过程中，ν(C═C)和ν(C═O)的振动频率呈现相反的位移，这可能意味着蒽醌及其连接的羰基的共振结构发生了变化。除了DMSO溶剂分子的溶剂化动力学外，还观察到了茜素质子转移互变异构体势能面上的振动弛豫以及两个不同时间尺度上发生的布居衰减。
