含能材料分子激发态能量弛豫过程的时间分辨光谱研究

Ultrafast vibrational spectroscopy technique, femtosecond time-resolved coherent anti stokes k Raman Scattering (fs - CARS) and femtosecond time-resolved transient grating spectroscopy (fs - TG), is designed in this research to excite the selected vibrational mode of energetic molecule and probe its relaxation dynamics. It is a unique time-resolved vibrational spectroscopy technique for the investigation on molecular vibrational dynamics of excitation and relaxation of the energetic molecules. The advantage of this ultrafast vibrational spectroscopy technique is that it can excite the vibrational modes in electronic excited states and in the ground states respectively through the tuning excitation wavelength, and it is much better than ultrafast infrared spectroscopy which can only excite and detect single vibrational mode. Therefore，it can give the details of energy relaxation，energy transfer among the different vibrational modes and their competition processes. During this research，the obtained experimental data of ultrafast molecular reaction dynamics，and the law of energy relaxation and energy transfer，the built experimental methodology and facilities，will be the foundation for the further study of excitation process，reaction channel mechanism problems of complex explosives.

本项目设计的振动模式/能量状态选择性激发与光谱探测技术—飞秒时间分辨相干反斯托克思拉曼光谱技术（fs-CARS）及飞秒时间分辨瞬态光栅光谱技术（fs-TG），是针对分子振动能量激发与弛豫动力学过程研究所开发和完善的新型的时间分辨振动光谱技术。该超快振动光谱技术的优势是，通过调谐激发光波长，可将电子激发态和基态的振动结构区分开，突破以往时间分辨红外光谱的单一模式激发和探测的局限性，获得分子内不同振动模式能量弛豫、转移及竞争等动力学过程的细节。通过本项目的研究，所获得的在分子层次上含能材料超快反应过程的实验数据，分子激发态能量弛豫与转移规律，建立的实验方法和设施等，可为进一步研究复杂炸药分子激发过程与反应通道等机理问题提供技术支持和奠定研究基础。

本项目发展了振动模式/电子能态的选择性激发探测的超快时频分辨光谱技术—飞秒时间分辨相干反斯托克思拉曼光谱技术（fs-CARS）及飞秒时间分辨瞬态光栅光谱技术（fs-TG），实现了对分子内及分子间振动耦合过程的直接激发与观测，以及凝聚相含能材料电子激发态反应路径的直接观测，获得了几种典型模型分子振动模的耦合机制，以及电子激发态解离机制；发展的超快光谱技术方案及研究案例，对凝聚相有机分子反应的微观机制的研究，具有重要参考价值。