DESIGN OF A FLUORESCENCE TECHNIQUE USING DOUBLE LASER-PULSE EXCITATION FOR THE MEASUREMENT OF MOLECULAR BROWNIAN DYNAMICS

A complete analysis of a novel method to evaluate the rotational diffu sion time of fluorescent molecules is presented. It is based on the st udy of the total fluorescence produced after excitation with two conse cutive short laser pulses. Expressions for the total fluorescence ener gy emitted in this case are derived, which would allow the evaluation of the rotational diffusion time. The main advantages of the proposed method an its simple setup, a time resolution only limited by the exci ting laser pulsewidth, and the fact that it does not require fast time response detectors. (C) 1997 Elsevier Science B.V.