<title>Vibrational echo studies of proteins, liquids, and glasses</title>

Abstract

Ultrafast IR vibrational echo experiments, which are used to examine liquids, glasses, and proteins are described. Like the NMR spin echo and other NMR pulse sequences, the vibrational echo can extract dynamical and spectroscopic information that cannot be obtained from a vibrational absorption spectrum. The vibrational echo measures the homogeneous vibrational linewidth even if the absorption line is massively inhomogeneously broadened. When combined with pump-probe experiments, the homogeneous pure dephasing is obtained. Conducting these experiments as a function of temperature provides information in dynamics and intermolecular interactions. The nature of the method and the experimental procedures are outlined. Experimental results are presented for the metal carbonyl solute, Rh(CO)2acac, in liquid and glassy dibutyl phthalate. The dynamics of the CO ligand bound at the active site of the protein myoglobin is also examined and compared with that in several myoglobin mutants. The results provide insights into protein dynamics and how protein structural fluctuations are communicated to a ligand bound at the active site.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.