This grant in Experimental Physical Chemistry supports the research of Dr. Tomas Baer in the area of ion fragmentation mechanisms. This work studies the structure and dissociation dynamics of energy selected ions and ion-dipole complexes. It provides basic information on the properties and energy states of ions. Such information is necessary in a broad range of fields from upper atmosphere physics to solid state chemistry. This investigation will use photoelectron photoion coincidence, photodissociation, and IR photodissociation techniques to study cold ions such as nitrobenzene, propanol, and butadiene and ion-dipole complexes such as cyclopropane ion-water and ethylchloride ion-HCl. Differences between neutral and ionic dissociations, as revealed in terms of their mechanisms, rates of dissociation, and the role of excited states in the fragmentation step will be compared. Gross changes in the structures of the ions will be studied as a function of their internal energy. Special emphasis will be given to eludicating the effect the interaction potential between the departing fragments has on the dissociation rate and mechanism.
