Statistical Spectroscopy of Quantum Chaos State in Vibrationally Highly Excited polyatomic Molecules

本项目旨在东京、剑桥、格勒诺布尔和巴黎四个实验室对高激发多原子分子的分子内振动动力学进行实验和理论合作研究。高激发乙炔的振动动力学(1)MIT小组通过对振动高激发乙炔能级能的统计分析，提出了一个混沌振动动力学。(2) Grenoble小组基于MIT小组获得的光谱数据的傅里叶分析，提出了受激乙炔的不完全混沌动力学。(3) Tokyo组在单个振动能级上观察到乙炔的分散荧光光谱，获得了振动能级结构的全局特征。他们可以根据一个非调和展开函数来分析它，假设在大约14000 cm^<-1>的能量区域有五个正常模式。在此能量之外，两个CH弯曲模式（trans和cis）相互耦合，从而在这些模式中实现了局部混沌。与其他模态的耦合发生在接近最终完全混沌动力学的另一个阶段。(4)根据上述建议，MIT课题组基于乙炔的高分辨率SEP谱确认了两种CH拉伸模式之间的非谐波耦合方案。NO_2的单分子解离反应(1)东京基团成功地获得了NO_2的状态选择光片段（O或NO）激发谱。观察到的光谱呈线状结构，表明解离反应发生在N0_2的高激发振动态上。(2) Grenoble小组讨论了受激态N0_2的振动能级结构，并预测在解离阈值以下的区域也存在混沌能级结构。(1)东京研究组利用LIF光谱和光学-光学双共振方法预测了HgAr_2配合物的结构。(2) Orsay小组基于半经验计算的势面和共振增强的多光子电离方法讨论了HgAr_2的结构。少

This project aims at cooperative experimental and theoretical studies on intramolecular vibrational dynamics of highly excited polyatomic molecules which have been carried out in four laboratories of Tokyo, Cambridge, Grenoble and Paris.1. Vibrational dynamics of highly excited acetylene(1) MIT group proposed a chaotic vibrational dynamics by means of a statistical analysis of level energies of vibrationally highly excited acetylene.(2) Grenoble group claimed an incomplete chaotic dynamics of excited acetylene based on the Fourier analysis of the spectral data obtained by MIT group.(3) Tokyo group observed a dispersed fluorescence spectrum of acetylene in a single rovibronic level to obtain a global feature of the vibrational level structure. They could analyze it in terms of an anharmonic expansion function assuming five normal modes in an energy region up to around 14, 000 cm^<-1>. Beyond this energy, two CH bending, modes (trans and cis) couple each other, so that a local chaotic dy … More namics is realized within these modes. Couplings to other modes occur in another stage approaching a final full chaotic dynamics.(4) Following the above proposal, MIT group confirmed an anharmonic coupling scheme between two CH stretching modes based on the high-resolution SEP spectrum of acetylene.2. Unimolecular dissociation reaction of NO_2(1) Tokyo group succeeded to take a state-selected photofragment (O or NO) excitation spectrum of NO_2. The observed spectrum showed a line structure which indicated the dissociation reaction via highly excited vibrational states of N0_2.(2) The vibrational level structure of excited N0_2 was discussed by Grenoble group, who predicted a chaotic level structure even in the region below the dissociation threshold.3. Structure and dynamics of electronically excited van der Waals complexes(1) Tokyo group predicted the structure of HgAr_2 complex by means of LIF spectroscopy and optical-optical double resonance method.(2) Orsay group discussed the structure of HgAr_2 based on a semi-empirical calculation of the potential surface as well as resonantly enhanced multiple photon ionization method. Less