Hannover 2003 – wissenschaftliches Programm
MO 6.21: Poster
Dienstag, 25. März 2003, 16:00–18:30, Lichthof
Sub Picosecond Mid-IR Induced Molecular Dissociation — •Lars Windhorn1, Jake S. Yeston2, Thomas Witte1, Werner Fuss1, Marcus Motzkus1, Detlev Proch1, C. Bradley Moore3, and Karl-Ludwig Kompa1 — 1MPI für Quantenoptik, D-85741 Garching — 2NIST, Gaithersburg, MD 20899, USA — 3The Ohio State University, Columbus, OH 43210, USA
Chemical reactions proceed in general via bond changes in the electronic ground state and are thus induced by vibrational bond excitations. For many years experimentalists trying to achieve selective bond excitation were hindered by fast intramolecular vibrational-energy redistribution (IVR). The deposited energy was statistically coupled to all other vibrational modes on an ultrafast time scale, leading to non-selective reaction behavior. By using femtosecond laser pulses in the mid-infrared we have excited the asymmetric CNN stretching vibration in diazomethane (CH2N2) and induced directed scission of the C-N bond. Laser-induced fluorescence detection (LIF) of 1CH2 has revealed product formation on a sub-picosecond time scale, faster than the statistical limit.