A STOCHASTIC-MODEL FOR DUAL FLUORESCENCE OF DMABN IN POLAR MEDIA

A stochastic model for interpreting the dual fluorescence emission of dimethyl-aminobenzonitrile is presented, which takes into account the conformational dynamics of the singlet state S1, the emission dynamics to the ground state S0 and the relaxation of the polar solvent. The p robability density for the population of the excited state is determin ed by solving numerically a bidimensional diffusive operator for a tor sional variable of the molecule coupled to a solvent coordinate, with source and sink terms. The resulting diffusion equation is the continu ous analogue of the well known Grabowski kinetic scheme. The fluoresce nce emission is evaluated by integrating over the microscopic coordina tes at each emission frequency.