MIDIT OFD CATS Modelling, Nonlinear Dynamics Optics and Fluid Dynamics Chaos and Turbulence Studies and Irreversible Thermodynamics Risø National Laboratory Niels Bohr Institute and Technical University of Denmark Building 128 Department of Chemistry Building 321 P.O. Box 49 University of Copenhagen DK-2800 Lyngby DK-4000 Roskilde DK-2100 Copenhagen Ø Denmark Denmark Denmark
by Dr. Peter Hamm
Max Born Institut,
Max Bornstr. 2A,
12489 Berlin, Germany,
Tuesday, May 8, 2001, 14.00 h
at IMM, Bldg. 305, Room 018, DTU
Abstract: It has been speculated many years ago that delocalized and/or self- localized vibrational states in alpha-helices might play an important role for one of the most remarkable - yet not understood - property of proteins and enzymes, namely their capability to store and transport small quanta of energy in an extremely efficient manner. We are utilizing nonlinear femtosecond spectroscopic methods with the aim to understand the nature of these states and the coupling mechanisms giving rise to them. Since the nonlinear spectroscopic response of a harmonic system vanishes exactly, these experiments are particularly sensitive to the nonlinearities of the molecular Hamiltonian. Different coupling mechanisms are discussed on several examples, such as tri-peptides, alpha-helices and crystalline acetanilid (ACN), which is a commonly used model system for quasi-one- dimensional chains of hydrogen bonded peptide units.