Event Information
Michael Fayer
(Stanford University)
Dynamics of Molecular Complexes Probed with Ultrafast Infrared Nonlinear Experiments
Physics/Chemistry Colloquium
Dynamics of Molecular Complexes Probed with Ultrafast Infrared Nonlinear Experiments
- Abstract:
- Ultrafast infrared methods are applied to the study of the dynamics of molecular complexes. One fundamental type of molecular complex is hydrogen bonded water. The dynamics of nanoscopic pools of water in reverse micelles are directly investigated for the first time using frequency selective infrared stimulated vibrational echo experiments and infrared pump-probe rotational anisotropy measurements performed on the hydroxyl stretching mode of water. The nanopool data are substantially different from the bulk water data and show a clear size dependence. Another important molecular complex involves the formation and dissociation of solute-solvent complexes, which in the past have been too rapid to measure without disturbing the thermal equilibrium. For the first time this goal is achieved using ultrafast two-dimensional infrared vibrational echo spectroscopy, an ultrafast vibrational analogue of two- dimensional NMR. The equilibrium dynamics of phenol complexation to benzene in a benzene-CCl4 solvent mixture were measured in real time by the appearance of off-diagonal peaks in the two-dimensional vibrational echo spectrum of the phenol hydroxyl stretch.
Host: Glenn Edwards
Physics/Chemistry Colloquium