H-atom detachment photochemistry of (hetero)aromatic molecules: ab initio quantum dynamics studies

（杂）芳香族分子的氢原子脱离光化学：从头算量子动力学研究

基本信息

批准号：
248983919
负责人：
Professor Dr. Wolfgang Domcke
金额：
--
依托单位：
Lehrstuhl für Theoretische Chemie
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2014
资助国家：
德国
起止时间：
2013-12-31 至 2017-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/248983919?language=en
关键词：
atom detachment photochemistry hetero aromatic

项目摘要

When aromatic or heteroaromatic molecules with acidic groups (NH, NH2, OH, SH) are excited with ultraviolet (UV) light, the detachment of slow as well as fast hydrogen atoms is observed. These photodissociation processes are currently under extensive experimental scrutiny by means of modern photofragment detection techniques, which provide detailed quantum state-resolved information on this novel nonstatistical unimolecular decay process. In this research project, the electronic and quantum dynamical mechanisms of ultrafast H-atom detachment processes in selected (hetero)aromatic molecules will be explored by means of accurate ab initio electronic-structure and nuclear-dynamics calculations. The three representative molecules to be studied are pyrrole, phenol and thiophenol. Their hallmark is the existence of a conical intersection of the repulsive potential-energy function of a dark electronic state of pisigma* character with the attractive potential-energy function of the electronic ground state in the hydrogen-detachment channel. In phenol and thiophenol, an additional conical intersection between the lowest pipi* state and the pisigma* state is located in the Franck-Condon region. The goal of the project is (a) the construction of accurate ab initio based multi-dimensional diabatic potential-energy surfaces of the coupled electronic states involved in the photodissociation reaction and (b) the elucidation of the photodetachment mechanisms with time-dependent quantum dynamical calculations, in particular the effects of strong nonadiabatic interactions on the absorption spectrum and the final-state distribution of the photofragments. The intention is the rationalization of the rich amount of recent experimental data and the clarification of controversies concerning the assignment of the vibrational structures of the high-resolution H-atom kinetic-energy spectra.

当带有酸性基（NH，NH2，OH，SH）的芳族或异源分子被紫外线（UV）光激发时，观察到慢速和快速氢原子的脱离。这些光解离过程目前通过现代光片片检测技术进行了广泛的实验审查，该技术提供了有关这一新型非统计非分子衰减过程的详细量子状态分辨信息。在该研究项目中，将通过准确的AIT IBLION电子结构和核能计算来探索所选芳香族分子中超快H原子分离过程的电子和量子动力学机制。要研究的三个代表性分子是吡咯，苯酚和硫醇。它们的标志是存在Pisigma*特征的深色电子状态的排斥潜在能量功能的圆锥形相交，具有在氢检测通道中电子基态的吸引人的潜在能量功能。在苯酚和硫苯酚中，最低的PIPI*状态与Pisigma*状态之间的额外圆锥形相交位于弗朗克 - 康登地区。 The goal of the project is (a) the construction of accurate ab initio based multi-dimensional diabatic potential-energy surfaces of the coupled electronic states involved in the photodissociation reaction and (b) the elucidation of the photodetachment mechanisms with time-dependent quantum dynamical calculations, in particular the effects of strong nonadiabatic interactions on the absorption spectrum and the final-state distribution of the photofragments.目的是合理化了大量最近的实验数据，以及关于高分辨率H原子动力学能源光谱的振动结构分配的争议的澄清。