Picosecond time resolved energy transfer between rhodamine 6G and malachite green

The process of singlet—singlet resonance energy transfer between rhodamine 6G (donor) and malachite green (acceptor) has been studied with a picosecond laser : streak camera system. Unlike previous investigations, the measurements were conducted in a low viscosity solvent (ethanol) at room temperature. The donor fluorescence decay function was found to be in agreement with that predicted by the Förster theory over a tenfold range of acceptor concentrations (10^?3 M to 10^?2 M) and up to a limiting time resolution of 10 ps. An average R₀ value of 52.5 A was obtained from the fluorescence decay curves, in reasonable agreement with the value of 48 A calculated from spectroscopic data.