Progress in ultrafast dynamics of "Optics dark state" of China 's molecular system
Recently, Professor Zhang Qun from Professor Luo Yi's research team at the University of Science and Technology of China, made a great progress in the study of the ultrafast dynamics of the "optical dark state" (spin forbidden triplet state) of the condensed phase molecular system. How to effectively detect the dynamical evolution of the spin-forbidden excited triplet ("optical dark state") space has always been a thorny problem that has drawn considerable attention in the fields of photophysics, photochemistry and photobiology. Due to the rapid relaxation process such as internal conversion and intramolecular vibrational energy redistribution, it is very difficult to extract and characterize the dynamic evolution occurring in the "optical dark state" space. To this end, team researchers found another way to exploit the rapid energy transfer (intersystem crossing) of highly excited "optical states" (spin-allowed singlet states) to "optical dark states" (spin-forbidden triplet states) An unconventional "time-reversed femtosecond pump-detection" technique realizes "pure" ultra-fast kinetic evolution in the "optical dark" space in the model molecular system (malachite green molecule) Real-time tracking and characterization. The development of this nonlinear spectroscopy opens up a new window for molecular luminescence, photonics, and quantum-chemical research. The research was published in Phys. Chem. Chem. Phys. 17, (2015). The first author of the dissertation was Ge Jing, a Ph.D. candidate. His research was supported by Professor Jiang Jun Strong support for spectral and kinetic simulations. Researchers follow this research train of thought, in collaboration with Wang Chunru, a researcher at the Institute of Chemistry, Chinese Academy of Sciences, conducted an ultrafast kinetic mechanism study of metal-embedded fullerene molecules. By choosing a typical metal-embedded fullerene molecule Sc2C2 @ C82 and using femtosecond time-resolved ultrafast spectroscopy, three different carbon cage symmetries (Cs, C2v, C3v) and the same carbon cage Symmetry and Exocentric Modification of Visible Light Excited Electron Dynamic Behavior of a Molecular Group with Different Electronic Properties (Electron Donor / Receptor). Combined with the first-principles calculations, we found for the first time a high degree of correlation between the opening of triplet channels and the symmetry of fullerenes and the electronic properties of the extramolecularly-modified molecular groups in the molecular system, revealing the "optical dark state "Plays a decisive role in manipulating the evolution of its photo-excited electron dynamics. These studies have found that this mechanism provides a universal mechanism for the research and development of photoelectric conversion based on the metal-embedded fullerene molecular system for solar visible light utilization. The research was published in the Journal of the American Chemical Society [J. Am. Chem. Soc. 137, 8769 8774 (2015)]. The first co-authors of the dissertation are PhD students Wu Bo, Hu Jiahua and postdoctoral Cui Peng. The above work has been funded by the Ministry of Science and Technology, the National Natural Science Foundation of China and the CAS. Cummins kta50,kta50,Motor Cummins kta50,Cummins kta50 Engine,Cummins ktta50 Chongqing TC Machinery Co.,Ltd , https://www.techcummins.com