Wesley Allen of the University of Georgia is supported by an International Collaboration in Chemistry (ICC) award in the Chemical Structure, Dynamics, and Mechanisms program of the NSF Division of Chemistry for a joint theoretical/ experimental study of hydrogen tunneling in carboxylic and amino acids. The research is performed in collaboration with Professor Peter R. Schreiner of the Justus-Liebig University of Giessen, Germany. The Deutsche Forschungsgemeinschaft (DFG) is the partner agency supporting the German side of the collaboration. Chemical reactivity is conventionally understood in broad terms of kinetic versus thermodynamic control, wherein the driving force is respectively the lowest activation barrier among the possible reaction paths or the lowest free energy of the final products. Very recent breakthroughs in the preparation and characterization of hydroxycarbenes (R-VC-VOH) have demonstrated that quantum mechanical tunneling is a third driving force that can supersede traditional kinetic control and govern reactivity based on nonclassical penetration of the potential energy landscape intervening reactant and product. The Allen and Schreiner research groups investigate the role of hydrogen tunneling in the conformational dynamics of organic compounds of biological significance, namely, -Ã‘-keto carboxylic acid (1) and -Ã‘ amino acid (2) paradigms. For this purpose, matrix isolation experiments in Germany are joined with high-level ab initio theory in the United States. This ICC award supports wide-ranging, innovative activities that comprehensively address NSF broader impacts criteria. The professional training and intellectual development of graduate students is a key mechanism for broader impacts, and thus the project revolves around Ph. D. students in American and German research groups that are ethnically diverse and strongly international in character. Theory students will travel from Georgia to the German laboratory for immersion in the experimental environment. Likewise, German students will visit Georgia to experience the realm of high-level theory. Advanced computational methods resulting from the theoretical research will be freely shared with the scientific community via the PSI electronic structure package. Undergraduate research projects involving computational applications of tunneling methods will be undertaken with the aid of the Ph. D. students.