Single-molecule kinetics

At its best, the study of solvent kies by the formalism given can be used to learn about proton content and activation in the transition state. For this reason it is known as the proton inventory technique. The kinetics of decay of the lowest-energy electronic excited state of 7-azaindole illustrates the technique.25 Laser flash photolysis techniques (Section 11.6) were used to evaluate the rate constant for this very fast reaction. From the results it was suggested that, in alcohol, a double-proton tautomerism was mediated by a single molecule of solvent such that only two protons are involved in the transition state. In water, on the other hand, the excited state tautomerism is frustrated such that two water molecules may play separate roles. Diagrams for possible transition states that can be suggested from the data are shown, where of course any of the H s might be D s. 

Ritort, F. Bustamante, C. Tinoco Ir., I., A two-state kinetic model for the unfolding of single molecules by mechanical force, Proc. Natl Acad. Sci. USA 2002, 99, 13544-13548... 

R. Rigler, J. Widengren, and U. Mets, Interactions and kinetics of single molecules as observed by fluorescence correlation spectroscopy, in Fluorescence Spectroscopy, New Methods and Applications (0. S. Wolfbeis, ed.), pp. 13-24, Springer-Verlag, Berlin (1993). 

These new methods of nonequihbrium statistical mechanics can be applied to understand the fluctuating properties of out-of-equilibrium nanosystems. Today, nanosystems are studied not only for their structure but also for their functional properties. These properties are concerned by the time evolution of the nanosystems and are studied in nonequilibrium statistical mechanics. These properties range from the electronic and mechanical properties of single molecules to the kinetics of molecular motors. Because of their small size, nanosystems and their properties such as the currents are affected by the fluctuations which can be described by the new methods. 

Hummer G, Szabo A. Kinetics from nonequilibrium single-molecule pulling experiments. Biophys J 2003 85 5-15. 

I. Tinoco, Jr. and C. Bustamante, The effect of force on thermodynamics and kinetics of single molecule reactions. Biophys. Chem. 102, 513—533 (2002). 

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