炸药分子激发态解离动力学研究

Explosives are widely utilized for military and civil use in many fields and the related problems on safety, reliability and application are concerned. The physical and chemical reactions in the detonation zone are ultrafast and complex, usually in the time and space scales of nanosecond-picosecond and micrometer-nanometer, respectively. Limited to the experimental conditions, the research on such issue is rare. It is worth pointing out that the dissociation processes of molecular explosive in the excited states are ultrafast, which are veritably reflected the non-equilibrium state. The ultrafast dissociation process is recognized as the transient mechanisms of the detonation process and also performs a vital role in its energy conversion process. It is urgent to carry out work on the interaction of photon and molecular explosive, in order to acquire the geometrical change and energy transfer process. The project aims to carry out research on the dissociation mechanism and process of molecular explosive in the excited state. It plans to detect dissociation products and ultrafast dynamics of molecular explosive in the excited states, by utilizing ultrafast pulse laser-mass spectroscopy method. The structural change and dissociation mechanisms in the excited states are carried out by quantum chemical calculations. The research will acquire important results on the major dissociation products, paths and ultrafast dynamics of molecular explosive. The structural change and energy transfer process will be also obtained, as well as the role of some key groups, such as nitro group. The results are important for study of ignition, molecular modification, safety and aging evaluation.

炸药广泛应用于军事和民用各个领域，其产生的安全性、可靠性及应用问题备受关注。炸药爆轰反应区的物理和化学变化发生在微纳米的空间尺度上、皮秒甚至飞秒的时间尺度上，因实验条件限制，目前相关研究开展比较少。炸药分子激发态解离过程真实地反映炸药分子的非平衡状态，接近于爆轰瞬态的机制，在爆轰能量转换过程中起着关键作用。深入研究炸药分子光致激光态解离过程，获得光子与炸药分子的相互作用及能量转移过程引起的结构和性能变化显得尤为重要，是亟需解决的基础科学问题。本项目拟研究炸药分子激发态解离机制及反应动力学过程，利用超短脉冲激光与质谱技术的实验平台，探测炸药分子解离产物和超快动力学过程，结合激发态结构及解离过程的理论计算，获得激发态解离的主要产物、解离路径及动力学过程，获得结构变化、能量转移过程及关键基团在解离过程中起到的作用，研究结果为炸药点火起爆、分子改性、安全性和老化评估等提供依据。

炸药广泛应用于军事和民用各个领域，其产生的安全性、可靠性及应用问题备受关注。激发态解离过程是炸药分子化学能转换过程的关键步骤，其反应机制接近于爆轰瞬态反应机制，解离产物的探测对于爆轰反应历程的研究有着重要的作用。本项目旨在研究炸药分子激发态解离机制及其反应动力学，获得典型炸药分子激发态解离的主要产物和动力学过程，理解炸药分子激发态的结构变化及能量转移，在分子尺度上为炸药爆轰、分子改性、安全性等提供科学依据。项目完成了炸药分子激发态解离动力学实验研究的总体技术方案、实验平台集成以及初步物理实验，并针对性低真空度下离子产物难以识别的技术问题，设计了激光场电离产物检测的超高真空靶室、并完成靶室的机械加工及总体集成，搭建完成了超高真空度下气体分子电离研究实验平台。开展了纳秒激光驱动金属箔加载炸药物理实验，给出了多种加载条件下炸药的界面粒子速度，认识了炸药在纳秒激光加载后爆轰反应历程。利用了超短激光场气体分子电离实验平台，完成了典型气体分子的强激光场电离实验研究，通过实验条件优化和激光参数调控，获得电离产物、离子价态及及其随激光功率密度的变化规律。开展了激发态解离过程中的分子结构和能量的理论计算，获得了激发态弛豫过程的几何结构变化及反应势能面，认识了激发态反应过程和能量转换机理。研究获得光子与炸药分子相互作用及能量转移所带来的结构与性能的变化，为炸药反应过程尤其是超快反应过程研究新的技术途径，为新型炸药分子设计、改性、安全性评估等提供新的方法，同时能够为新型的炸药点火起爆方式、含能材料加工、光辐照及安全性等问题的解决提供实验依据。