Photodissociation of alkyl iodides in helium nanodroplets. III. Recombination.
The recombination of fragments resulting from the photodissociation of (fluorinated) alkyl iodides in helium nanodroplets at a wavelength of 266 nm has been investigated by means of ion imaging techniques. It is found that in the case of CH3I an appreciable fraction of the fragments recombine in the aftermath of the photolysis. The proposed mechanism involves a complete translational relaxation of both photofragments inside the nanodroplets followed by geminate recombination of the fragments. In contrast with CH3I, no recombination is observed for CF3I. This is attributed to the larger masses and the different initial kinetic energies of the fragments produced by the photolysis of CF3I, which strongly diminishes the fragment thermalization efficiency.
Braun
Andreas
A
Laboratoire de Chimie Physique Moléculaire, Ecole Polytechnique Fédéral de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
Drabbels
Marcel
M