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SYND: Nonequilibrium Dynamics of Biomolecules

SYND 1: Sitzung 1

SYND 1.1: Invited Talk

Thursday, March 25, 2004, 14:00–14:30, HS 332

Theory and Design of Multidimensional IR Pulse Experiments — •Christoph Scheurer — Lehrstuhl für Theoretische Chemie, TU München, 85748 Garching

Femtosecond visible and infrared (IR) multiple-pulse techniques based on the control and manipulation of multiple quantum coherences provide new tools to probe the structure and dynamics of complex molecular assemblies. The control over time delays in a pulse sequence yields multidimensional spectra with increased resolution and information content as compared to 1-D experiments. Structural and dynamical information is contained in the position, shape, and temporal evolution of cross and diagonal peaks that are due to anharmonicities in the underlying system Hamiltonian and its coupling to the environment. Ultrafast laser pulses thus allow to obtain picosecond snapshot pictures of the molecular structure along dynamic trajectories. These experiments are theoretically best described in the framework of the density matrix formalism. In the weak-field limit a multiple-pulse experiment can be conveniently represented by a set of double-sided Feynman diagrams. The design of multidimensional vibrational spectroscopies can draw upon analogy with liquid or solid state nuclear magnetic resonance (NMR) spectroscopy which are well established for studying structure and dynamics of complex systems on slower timescales.