Investigation of intra- and intermolecular transfer processes by picosecond fluorescence gating

Fluorescence up-conversion is a promising technique for the investigation of ultrafast processes within and between poly-atomic molecules. Conditions are discussed for up converting broad-band fluorescence efficiently with a time resolution better than 1 ps. Experimental results are presented on vibrational relaxation in the first excited singlet state, internal conversion, and intermolecular energy transfer in liquid solutions.