It is proposed to apply the newly developed method of pulsed, time resolved photoacoustics to the study of photosynthesis and photoinitiated electron transfer reactions. This methodology allows the determination of the enthalpies of the initial reactions, that of the time resolved steps, and that of the slow reactants or stable products. The kinetics of photosynthetic and photochemical reactions are now well understood, and intermediate steps fairly well known. However, the thermodynamic parameters of these intermediates are only poorly known. Since the pulsed, time resolved photoacoustic methodology identifies a change in enthalpy with its kinetics, the latter can be used to identify the intermediate. The thermodynamic efficiency of the intact system: cell or a whole leaf, can be so studied. The results will allow a much better understanding of the energetics of the photosynthetic process and of electron transfer reactions. Dr. Mauzerall will also continue to work on the sizes of photosynthetic units and on the effect of the molecular environment on electron tunneling reactions.
