Abstract
Molecular luminescence in the near ir is produced by 259–290 nm pulsed ’’photodissociation’’ of CH3I, CD3I, and perfluoroalkyl iodide guests in rare gas hosts at 4.2 °K. For CD3I and CH3I in Ne, the 15 member progression observed is assigned as fluorescence into high lying (near v″=37) vibrational states of the methyl–iodide stretch in the ground electronic state. Photoselection studies confirm the transition dipole lies along the methyl–iodine bond. The photodissociation cage effect is near complete, with only a minor quantum yield of permanent dissociation. Detailed analysis of the spectra suggests that the 0+ ’’repulsive’’ excited state is actually slightly (<2000 cm−1) chemically bound, and that the ground state potential is negligibly perturbed from its free molecule shape. A simple semiquantitative theory of the cage effect is proposed. In the impulsive limit, the excited state dynamics reflect a strong cage effect. However, in the adiabatic limit, the absorption and emission spectra reflect only a weak, van der Waals cage effect. The theory is applied to known examples of photodissociation in solids, and to rearrangements of larger molecules. A cage potential experiment of Schnepp and Dressler is reinterpreted.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.