Time-Resolved Thermodynamic Properties of Intermediate Species during Photochemical Reactions

Abstract

Abstract Thermodynamics and kinetics are very large and important fields in science. However, experimental efforts to link these two fields have been very limited so far. For instance, although the themodynamical properties of transient species are essential for the knowledge of the nature and energetics of the reaction, such data have been very scarce. Kinetic study of a reaction from a view point of thermodynamic properties in the time domain should be very useful to detect a spectrally silent kinetic property. We have developed experimental methods to measure the time development of the thermodynamical properties of transient species without any assumption and without any temperature or pressure variations. Some of the results, in particular applications to reactions of biological proteins (photodissociation of the ligand of carboxymyoglobin, photo-reaction of Photoactive Yellow Protein (PYP) and octopus rhodopsin), are reviewed.