Spectrally separated fluorescence emissions for diesel fuel droplets and vapor.
Spectrally separated fluorescence emissions from liquid and vapor diesel fuel can be obtained by adding an exciplex-forming molecule to the fuel. The exciplex emission dominates the condensed phase emission, while the monomer emission dominates the vapor phase emission. In particular with the naphthalene/tetramethyl-p-phenylene diamine system, the liquid and vapor phase emissions peak at 470 and 380 nm, respectively. Results for droplets at 110 and 250°C are presented.