Zero-point level isotope effects in isolated molecules and hydrogen bonded solids

本课题由化学系实验物理化学项目资助，由布鲁斯S.锡拉丘兹大学的哈德逊将研究氢键的性质，特别关注分子零点能的变化和伴随氢氘交换过程的晶体相变。主要的实验技术是振动非弹性中子散射（INS）光谱和核磁共振光谱（NMR）。INS数据将在联合王国的ISIS设施和橡树岭国家实验室的SpO2中子源收集。将使用密度泛函理论（DFT）建模方法计算INS振动光谱。 DFT和其他量子化学方法将用于计算D取代对1H和13C NMR谱的影响。本研究的目的是建立在有机固体状态的氢键理论描述的有效性限制。这是合理设计纳米结构材料、非线性光学材料和有机电子器件、控制药物中的多晶型、预测球状蛋白质的结构或设计其功能抑制剂的必要条件。研究生和本科生以及博士后研究人员参与了这项研究。该研究将导致自组装有机结构中氢键相互作用的基本原理的发展，这些氢键相互作用是最重要的结构特异性相互作用，在室温下在环境条件下处于可逆平衡，因此对自组装有用。

In this project, funded by the Experimental Physical Chemistry Program of the Chemistry Division, Prof. Bruce S. Hudson of Syracuse University will investigate the nature of hydrogen bonding, with specific focus on the changes in molecular zero point energies and crystal phase changes that accompany hydrogen-deuterium exchange processes. The major experimental techniques used are vibrational inelastic neutron scattering (INS) spectroscopy and nuclear magnetic resonance spectroscopy (NMR). The INS data will be collected at ISIS facility in the United Kingdom and the Spallation Neutron Source at Oak Ridge National Laboratory. Density functional theory (DFT) modeling methods will be used to compute the INS vibrational spectra. DFT and other quantum chemical methods will be used to compute the effect of D substitution on 1H and 13C NMR spectra. The objective of this study is to establish the limits of validity of theoretical descriptions of hydrogen bonding in the organic solid state. This is a necessary condition for the rational design of nanostructured materials, nonlinear optical materials and organic electronic devices, for the control of polymorphism in pharmaceuticals and in predicting the structures of globular proteins or designing inhibitors of their function.Graduate and undergraduate students participate in this research, as well as postdoctoral research associates. The research will lead to the development of fundamentals of hydrogen bond interaction in self-assembling organic structures, which are the most important structure-specific interactions that are in reversible equilibrium at room temperature under ambient conditions and thus useful for self-assembly.