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

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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.