Resolution of a long lived fluorescence component from D1/D2/ cytochrome b‐559 reaction centres

D1/D2/cytochrome b‐559 reaction centres rapidly degrade under continuous illumination. This is a problem in time‐resolved spectroscopy experiments. A long lived fluorescence component assigned to radical pair recombination has been reported previously, but contributing to less than 2% of the fluorescence. This letter reports that sample stability is significantly improved under anaerobic conditions. Fluorescence lifetime measurements described here assign 44% of the total fluorescence yield to a 36.5 ± 2.5 ns lifetime.