State, Time and Velocity Resolved Photofragment Translation-al Spectroscopy of Organic Iodides in the Gas Phase and in Solvated Clusters

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In this project in the Experimental Physical Chemistry Program of the Chemistry Division, photodissociation of isolated and solvated molecular iodine and organic iodides will be studied, and the dynamics will be analyzed in three sets of experiments. The first set will involve the development of a one-dimensional projection technique to determine the velocity distribution of the iodine fragment from the dissociation processes. The second set will involve femtosecond pump-probe techniques to measure the kinetic energy of the photofragments as a function of excess energy above the dissociation limit to gain information on the shape of the dissociating potential energy surface. The third set will involve the study of solvated iodine ions which are photodissociated and examined using mass-selected ion kinetic energy spectroscopy, from which the fragmentation dynamics are deduced. %%% The study of photodissociation processes of polyatomic molecules, that is, the fragmentation of molecules with many atoms using light, can reveal a great deal about the electronic forces which shape the behavior of the molecules. In particular, the lifetimes of the molecules in an excited electronic energy state as well as the partitioning of the excess energy among the fragments when an electronically excited molecule decomposes can be determined. This information in turn can give a detailed picture of the potential energies which govern the behavior of dissociating fragments, which in turn can be related to the behavior of the species in condensed (liquid or solid) phases. Such experimental spectroscopic studies of the photodissociation of polyatomic molecules are the goal of the current project.