Internal Rotation Potential Surfaces

罗格斯大学的莱昂内尔·古德曼在实验物理化学计划的支持下，继续他对非刚性小分子和芳烃内旋转的理论和实验研究。他将通过将他早期的驰豫研究扩展到其他甲基分子和其他转子，来研究母体分子框架的弯曲对内部旋转势表面的影响。涉及里德堡跃迁的双光子喷射光谱学和零动能光电子能谱将与布鲁克海文的迈克·怀特合作，用来获得关于基态、自由基阳离子和里德伯格态高位扭转势垒的形状和高度的信息。电子结构计算也将使用逐步松弛来确定键弯曲，并使用涉及极化和漫射函数以及相关能级的一些基组。分子中甲基的扭转运动目前正在被深入研究，因为它们为分子内振动能量重新分配(IVR)问题提供了洞察力。通过激光激发控制化学反应的目标需要了解激发能量如何流入各种可能的反应通道。甲基扭转运动可以在光谱的可及区域内研究，为跟踪IVR提供了一个一维的理论模型。

Lionel Goodman of Rutgers University is supported by the Experimental Physical Chemistry Program to continue his theoretical and experimental studies on internal rotation in small nonrigid molecules and aromatics. He will study the effect of flexing of the parent molecule frame on the internal rotation potential surfaces by extending his earlier relaxation studies to other methyl molecules and other rotors. Two-photon jet spectroscopy involving Rydberg transitions and zero-kinetic energy photoelectron spectroscopy, in collaboration with Mike White of Brookhaven, will be exploited to yield information on the shape and height of ground state, radical cation and high lying Rydberg state torsional potential barriers. Electronic structure calculations will also be undertaken using stepwise relaxations to determine the key flexings, and using a number of basis sets involving polarization and diffuse functions, and correlation levels. The torsional motions of methyl groups in molecules are presently under intensive investigation for the insight that they provide to the problem of intramolecular vibrational energy redistribution (IVR). The goal of controlling chemical reactions by laser excitation requires an understanding of how the excitation energy flows into various possible reaction channels. Methyl group torsional motions can be studied in an accessible region of the spectrum and offer a one dimensional theoretical model for tracking IVR.