物理化学学报 >> 2014, Vol. 30 >> Issue (12): 2216-2223.doi: 10.3866/PKU.WHXB201410221

热力学,动力学和结构化学 上一篇    下一篇

4-硝基咪唑A-带激发态结构动力学

李丹, 薛佳丹, 郑旭明   

  1. 浙江理工大学化学系, 先进纺织材料教育部重点实验室, 生态染整技术教育部工程中心, 杭州 310018
  • 收稿日期:2014-09-12 修回日期:2014-10-22 发布日期:2014-11-27
  • 通讯作者: 郑旭明 E-mail:zhengxuming126@126.com
  • 基金资助:

    国家自然科学基金(21033002, 21202032)和国家重点基础研究发展规划项目(973) (2013CB834604)资助

Excited State Structural Dynamics of A-Band of 4-Nitroimidazole

LI Dan, XUE Jia-Dan, ZHENG Xu-Ming   

  1. Department of Chemistry, and Key Laboratory of Advanced Textiles Materials and Manufacture Technology of the Ministry of Education, and Engineering Research Center for Eco-Dyeing and Finishing of Textiles of the Ministry of Education, Zhejiang Sci-Tech University, Hangzhou 310018, P. R. China
  • Received:2014-09-12 Revised:2014-10-22 Published:2014-11-27
  • Contact: ZHENG Xu-Ming E-mail:zhengxuming126@126.com
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21033002, 21202032) and National Key Basic Research Program of China (973) (2013CB834604).

摘要:

通过共振拉曼光谱实验和量子化学计算的方法研究了4-硝基咪唑(4NI)A-带激发态衰变动力学. 对4NI的振动光谱、紫外电子吸收光谱、荧光光谱和共振拉曼光谱进行了指认. 在全活化空间自洽场法(CASSCF)/6-31G(d)计算水平下获得了单重激发态S1(nOπ*)和S2(ππ*)和势能面交叉点S1(nOπ*)/S2(ππ*)的优化几何结构和能量, 分析了A-带共振拉曼光谱的强度模式特征, 获得了短时结构动力学, 并结合全活化空间自洽场法(CASSCF)理论计算结果确定了4NI 在S2(ππ*)态衰变通道主要是S2, FCS2, min(ππ*)→S0辐射弛豫.

关键词: 4-硝基咪唑, 结构动力学, 共振拉曼光谱, CASSCF计算, 振动光谱, 电子光谱

Abstract:

The A-band structural dynamics of 4-nitroimidazole (4NI) were studied using resonance Raman spectroscopy and quantum mechanical calculations, and the vibrational spectra, UV absorption spectra, fluorescence spectra, and A-band resonance Raman spectra were assigned. The resonance Raman spectra of 4-nitroimidazole were obtained in methanol with excitation wavelengths in resonance with the first intense absorption band, to probe the short-time structural dynamics. The optimized geometric structures and the excitation energies of the singlet excited states S1(nOπ*) and S2(ππ*), and the conical intersection point S1(nOπ*)/S2(ππ*), were computed at the complete active space self-consistent field (CASSCF)/6-31G(d) theory level. The intensity patterns of the A-band resonance Raman spectra were analyzed, and the results, together with those of the CASSCF calculations, revealed that the major decay channel initiated from the S2(ππ*) state was S2, FCS2, min(ππ*)→S0 radiation.

Key words: 4-Nitroimidazole, Structural dynamics, Resonance Raman spectrum, CASSCF calculation, Vibrational spectrum, Electronic spectrum

MSC2000: 

  • O643