Structure and Dynamics of Isolated Molecular Clusters

在化学系物理化学计划的这个项目中，宾夕法尼亚大学的迈克尔·托普教授将使用冷却喷射膨胀中的皮秒分辨偏振光谱来研究分子团簇的结构和动力学。TOPP建议使用时间域旋转相干技术来获得关于星团的结构信息，以便了解这些有序系统中的能量转移和相关过程。这样的信息很难用更正常的频率分辨光谱技术获得。芳香族分子perene将用于许多结构工作，涉及不同烷烃和具有较大静电相互作用的各种极性和不饱和分子的络合。吸收和发射可见光的大有机分子使原子或分子的小团簇成核，这为研究溶液中较大规模的分子间力和分子在延伸表面上的吸附提供了宝贵的机会。激光可以用来激发这些大的有机分子，然后可以在非常快的时间尺度上跟踪相关团簇的时间演化，以便能够确定这些微观组织系统的结构和动力学。这些信息可能会对许多领域产生影响，包括催化和生命过程的化学。

In this project in the Physical Chemistry Program of the Chemistry Division, Professor Michael Topp of the University of Pennsylvania will use picosecond-resolution polarization spectroscopy in cooled jet expansions to study structure and dynamics in molecular clusters. Using the time-domain rotational coherence technique, Topp proposes to obtain structural information on clusters in order to understand energy transfer and related processes in these organized systems. Such information is difficult to obtain by more normal frequency resolved spectroscopic techniques. The aromatic molecule perylene will be used in much of the structural work, involving the complexation of different alkanes and various polar and unsaturated molecules with large electrostatic interactions. %%% The nucleation of small clusters of atoms or molecules by large organic molecules which absorb and emit visible light presents valuable opportunities to study intermolecular forces of the kind found on a larger scale in solutions and in the adsorption of molecules onto extended surfaces. Lasers can be used to excite these large organic molecules, and then the time evolution of the associated cluster can be followed on very fast time scales in order to be able to determine the structure and dynamics of these microscopic organized systems. Such information can have a bearing on many fields, including catalysis and the chemistry of life processes.