Chemical Dynamics of Isolated Carbenes

我们将继续研究开壳层物种，特别是卡宾的光化学和光解动力学。重点将放在与燃烧过程和星际空间的化学有关的分子上。由于开壳层系统的高反应性，我们将在气相中的无碰撞条件下研究它们。在所有的实验中，我们将用激光辐射激发分子，并使其存款足够的能量来引发化学反应。在本工作中采用的最重要的检测方法是速度图成像（VMI）的photorfragments，它允许提取详细的信息的光解动力学。我们将继续研究C3 H2异构体炔丙基的激发态结构和动力学。此外，我们将开始研究fulvenallene（C7 H6）和fulvenallenyl（C7 H5），这两种物质到目前为止几乎没有研究，但最近被确定为可能的中间体在烟灰形成。我们感兴趣的另一类化合物是相对稳定的卡宾，称为“Arduengo”-卡宾。 关于这类迷人的分子的激发态，我们所知甚少，以前我们主要集中在氢原子光碎片的分析上。我们现在将我们的工作扩展到甲基（CH 3）片段和氯原子的检测。检测甲基片段将使我们能够研究开壳物种中的C-C键断裂，这是一个迄今为止很少研究的途径。用这种方法，我们想完成我们的研究的烷基正丙基和叔丁基。氯原子的检测允许照亮卡宾的光化学动力学的重原子的影响。我们将比较卡宾c-C3 H2和c-C3 HCl以进一步解决这个问题。此外，我们计划通过与外部合作伙伴的选定项目来补充我们的研究计划。飞秒时间分辨光电子能谱将研究光激发后的超快过程。将使用IR/UV双共振光谱来阐明与燃烧相关的双分子反应。由于需要高通量中红外光源，因此实验将在自由电子激光源处进行。

We will continue to investigate the photochemistry and photodissociation dynamics of open shell species, in particular carbenes. The focus will be on molecules that are relevant to the chemistry of combustion processes and interstellar space. Due to the high reactivity of open-shell systems we will study them under collision-free conditions in the gas phase. In all experiments we will excite the molecules with laser radiation and deposit sufficient energy to initiate a chemical reaction. The most important detection method employed in the present work is velocity map imaging (VMI) of photofragments, which permits to extract detailed information on the photodissociation dynamics. The following projects will be pursued: We will continue to study the excited state structure and dynamics of the C3H2 isomer propargylene. Furthermore we will start to investigate fulvenallene (C7H6) and fulvenallenyl (C7H5), two species that are so far hardly investigated, but were recently identified to be possible intermediates in soot formation. Another class of compounds of interest to us are relatively stable carbenes, termed "Arduengo"-carbenes. Little is yet known about the excited electronic states of this fascinating class of molecules.Previously we have concentrated on the analysis of H-atoms photofragments. We will now extend our work to the detection of methyl (CH3) fragments and chlorine atoms. Detecting methyl fragments will permit us to study C-C bond breaking in open shell species, a hithereto little investigated pathway. With this method we want to complete our investigation of the alkyl radicals n-propyl and t-butyl. Detection of chlorine atoms permits to illuminate the influence of heavy atoms on the photochemical dynamics of carbenes. We will compare the carbenes c-C3H2 and c-C3HCl to further address this issue.In addition we plan to complement our research program by selected projects with external partners. Ultrafast processes after photoexcitation will be investigated by femtosecond time-resolved photoelectron spectroscopy. Bimolecular reactions of relevance to combustion will be elucidated using IR/UV double resonance spectroscopy. Since a high flux mid-IR source is required, the experiments will be carried out at a free electron laser source.