Interpretation of Measurements of Photochemical Reactions in Focused Laser Beams

摘要

A method is described for obtaining the rate constant of the photodegradation process of fluorophores illuminated by focused laser beam. The explicit kinetic equations are averaged over the illuminated volume to describe the behavior of fluorescence for illumination modulated at low frequencies (1 Hz to 100 Hz). Solution of the kinetic equation for a complex modulation leads to an in-phase and quadrature components. The ratio of quadrature to in-phase components yields information on the photodegradation rate. Modeling is undertaken to explore the accuracy of the measurement of rate constants using the power modulation and synchronous detection technique.