This project, in the Inorganic, Bioinorganic, and Organometallic Chemistry Program, is concerned with the use of electron donor ligands that undergo irreversible fragmentation after photochemically induced electron transfer to probe the dynamics of excited state transition metal systems. In principle, the use of an irreversible chemical reaction that occurs after the electron transfer will allow for the determination of excited state dynamics that cannot be obtain by direct time resolved spectroscopic methods. The method will be applied to molecular and ion paired systems using nanosecond/picosecond transient absorption spectroscopy and quantum yield measurements. Absorption of electromagnetic radiation occurs with the formation of an excited state of absorbing molecule. What happens to this absorbed energy very much depends upon the lifetime of the excited state. This project is designed to acquire fundamental information about the behavior of excited states in a variety of transition metal compounds. Ultimately the information obtained from these studies may prove useful in developing better chemical methods of solar energy conversion.