Applications of laser-ion beam photodissociation for the study of diene systems and a study of the ion-molecule chemistry of ionic transition metal cluster fragments by ligand exchange reactions

Laser-ion beam photodissociation is utilized to study the dissociation dynamics of conjugated diene systems. Applications of the laser-ion beam photodissociation experiment provide useful information about dissociation dynamics, i.e., dissociation rates, photoexcited ion lifetimes, and structural information.;One application involved the study of the photodissociation of 1,3-butadiene. The laser-ion beam photodissociation experiments provide evidence of long lived photoexcited 1,3-butadiene radical cations. Additionally, the photodissociation of 1,3-butadiene was shown to proceed via one of two mechanisms; (i) direct photodissociation of photoexcited 1,3-butadiene ions or (ii) sequential two-photon photodissociation process for long lived photoexcited 1,3-butadiene ions. The photodissociation of 1,3-butadiene also provides evidence of a dependence upon instrumental parameters.;Another application of the photodissociation experiment utilizes a biased activation cell (BAC). The BAC provides information on the kinetics of dissociation. The BAC was utilized for probing the dissociation dynamics of 1,3-pentadiene and 2,4-hexadiene isomers. The BAC data can give a indication of the photodissociation rate and also provide structurally significant information allowing for isomer differentiation.;Secondly the ion-molecule chemistry of ionic transition metal cluster fragments is studied by ligand exchange reactions. The systems studied include Cr;The ligand exchange reaction studies are concerned with the products formed and with relative reactivities of each ionic cluster fragment. The relationship between reactivity and the coordination unsaturation of the ionic cluster fragments is probed. Additionally, the reactivity is compared to theoretical reaction rates, i.e., Langevin collision theory and the Average Dipole Orientation theory. The reactivity of the chromium ions are also compared to relative metal-metal bond strengths obtained from collision induced dissociation data.;The ligand exchange reactions observed for both the Cr...