DETERMINATION OF THE ORIENTATION DISTRIBUTION OF ADSORBED FLUOROPHORES USING TIRF .1. THEORY

The spectroscopic technique total internal reflection fluorescence can be used for determination of the orientation of adsorbed fluorescent molecules. The underlying theory is presented in general terms and ela borated in detail for the case that the fluorescent group is a porphyr in ring. It is shown that order parameters of the orientation distribu tion can be obtained if both the fluorescence intensity and its polari zation are measured as functions of the polarization of the incident l aser beam. From these order parameters an approximation of the orienta tion distribution can be derived by the maximum-entropy method.