Femtosecond Dynamics of Unimolecular and Unrestricted Bimolecular Reactions
نویسندگان
چکیده
The results of two time-resolved experiments using femtosecond laser pulses are presented. In the first, molecular photoinduced detachment of I2 from methylene iodide is studied. The progress of the reaction is monitored by selective detection of fluorescence from the iodine product; molecular dynamics are probed by depletion of the fluorescent state. Pump-probe spectroscopy of the halogen moiety following high-energy (12 eV) excitation reveals that the reaction proceeds by a concerted asynchronous mechanism. The second experiment is a real-time study of an unrestricted bimolecular reaction. In this process, gas phase mercury atoms are photoassociated to an electronically excited state using a femtosecond pulse; the real-time dynamics of the resulting excimers are probed by fluorescence depletion using a second pulse. Analysis of the rotational anisotropy in the nascent dimers reveals the degree of rotational excitation in the excited state and indicates the impact parameter selectivity of the photoassociation process.
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