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Volume 119, Issue 2, 08 July 2003
Getting ahead of IVR: A demonstration of mid-infrared induced molecular dissociation on a sub-statistical time scale119(2003); http://dx.doi.org/10.1063/1.1587696View Description Hide Description
Gaseous diazomethane has been irradiated with femtosecond laser pulses tuned to the CNN asymmetric stretch at 2100 cm−1 in the mid-infrared. Laser-induced fluorescence detection of [537 nm, confirms infrared (IR) multiphoton-induced scission of the C–N bond on two distinct time scales, 480±70 fs and 36±8 ps. The longer time scale is consistent with a statistical dissociation process; the shorter one is indicative of directed dissociation, which occurs more rapidly than statistical intramolecular vibrational energy redistribution because of direct coupling of the vibrational energy from the IR-excitation mode into the reaction coordinate. Anisotropy measurements demonstrate that the group bends significantly out of the molecular plane prior to the dissociation.