几种香豆素氢键团簇的光物理性质及动力学过程研究

The studies on photophysical properties and dynamics process of hydrogen-bonded coumarin clusters have drawn greater attention and recently become the research hotspot of atomic and molecular physics. .This research project is composed of four aspects: (1) Using the time dependent density functional theory method, we will optimize the geometrical configurations of the eight derivatives of 1,2-benzopyrone as well as their hydrogen-bonded coumarin clusters formed with four solvent molecules such as water and investigate the changes of the structural parameters of the hydrogen-bonded clusters upon photoexcitation. (2) The electronic spectra, infrared and Raman spectra as well as hydrogen bonding energies of the hydrogen-bonded coumarin clusters will be calculated and analysed to clarify the influences of the intermolecular hydrogen bonding interactions on the photophysical processes of the hydrogen-bonded clusters.(3) For each hydrogen-bonded coumarin cluster, the hydrogen-bond coordinate potential energy curves at different electronic states will be constructed, based on which the microscopic mechanism of the dynamics processes such as proton transfer, etc. will be explored.(4) Theoretical model and empirical formula will be founded to describe the influences of hydrogen bonds of different types and numbers as well as their strength changes on the electronic spectra, infrared and Raman spectra of the clusters. The implementation of this research project will expand our knowledge about the microscopic action mechanism of the dynamics process of the hydrogen-bonded cluster and will provide data for the applied researches of dye laser, electroluminescent materials, fluorescent probe, etc.

香豆素氢键团簇的光物理性质及动力学过程的研究倍受人们的关注，是当前原子分子物理学的热点问题。.本项目的研究内容包括如下四个方面：一、采用含时密度泛函理论等方法优化1,2-苯并吡喃酮衍生出的八种香豆素分子及其与水等四种分子形成的若干类香豆素氢键团簇的空间构型，研究其结构参数在光激发过程中的变化情况；二、计算上述香豆素氢键团簇的电子光谱、红外和拉曼光谱及分子间氢键的结合能，分析比较其在光激发过程中的变化规律，阐明分子间氢键作用对团簇光物理过程的影响；三、通过构造氢键坐标势能函数，分析比较其在不同电子态的差异，探索团簇内质子转移等动力学过程的微观机理；四、构建理论模型并建立经验公式，描述团簇内不同类型、不同数目的氢键及其强度变化对团簇电子光谱、红外及拉曼光谱的影响。项目的研究将加深对氢键团簇动力学过程微观作用机理的认识，为燃料激光器、电致发光材料、荧光探针等领域的应用研究提供数据。

基于所选取的八种香豆素分子与四种溶剂分子，优化得到各种组合方式的氢键团簇在基态、激发态的空间稳定构型，对比分析其结构参数的变化，发现香豆素C500分子氢键团簇的吸收谱峰值以及粘合程度都与溶液极性函数呈线性相关。优化得到以香豆素C500为母体分子的三氢键体系在溶液中稳定存在的分子构型。在一些氢键团簇结构中观测到的激发态氢键加强现象，可以引起特征官能团的红外振动谱峰值红移。同样由于氢键强度的变化改变了分子的耦合和共轭程度，也会引起团簇的吸收光谱和荧光光谱峰值产生显著的红移或蓝移。.在经过相关泛函、基组测试后，我们固定一系列的氢键键长或二面角，对团簇构型基态及激发态进行柔性优化，逐点扫描得出对应的团簇能量，用来构造基于键长和二面角的二维氢键坐标势能函数，对氢键变化引起电荷转移、质子转移等现象的微观机理进行解释，取得一系列优秀的成果。发现基态与激发态下，甲酸基二萘嵌苯（FPe）分子和甲醇分子间氢键均能促进电荷转移，并且氢键强度随着FPe分子上吸附的甲醇的增加而增强；解释了二氢键体系苯酚-硼烷-三甲胺分子(P-BTMA)激发态脱氢过程及其羟基裂解、构型异变现象；利用分子间氢键激发态加强理论描述并解释了苯并恶唑衍生物分子的分子内质子转移过程；构建三维势能面图，直观揭示激发态分子内双质子转移过程等。另外，我们还积极地将相关工作拓展至其他领域，利用氢键研究了除污吸附、生物催化的“双态反应”(TSR)机理、有机半导体迁移率调控等方面，并取得较为满意的成果。.项目的研究加深了对氢键团簇动力学过程微观作用机理的认识，为燃料激光器、电致发光材料、荧光探针等领域的应用研究提供了丰富的数据