Picosecond laser photolysis studies on a photochromic dithienylethene in solution and in crystalline phases

Picosecond transient absorption spectroscopy and fluorescence measurement were applied to the direct observation of photochromic reaction of 1,2-bis(2,5-dimethyl-3-thienyl)perfluorocyclopentene (DMTF) in solutions as well as in crystalline phase. In both phases, very rapid (⩽ ≈ 10 ps) reaction channel of the ring-closure was found. the mechanism of ultrafast reaction process was discussed by comparing the present result with those of other diarylethene derivatives.