Single conformation spectroscopy of peptides and synthetic foldamers Timothy S. Zwier Department of Chemistry, Purdue University, West Lafayette, IN 47907-2084 U.S.A. The infrared or ultraviolet spectroscopy of large molecules with biological relevance is challenging in that the spectra often are a composite of absorptions from many conformational isomers whose individual contributions are hard to decipher. This talk will describe experimental methods used in our group at Purdue to study such molecules under isolated molecule conditions, combining laser desorption, supersonic cooling, and mass-resolved, resonant two-photon ionization spectroscopy. The infrared and ultraviolet spectra of individual conformations are probed using double-resonance laser spectroscopy. These spectra directly probe the intramolecular and intermolecular H-bonding networks formed, providing insight to the inherent conformational preferences of the molecules in the presence and absence of a controlled number of solvent molecules. Results from recent studies of synthetic foldamers, peptides, and water clusters bound to a model aromatic binding pocket will be described.