Raman spectroscopic study on isomers of photochromic 1,2-bis(2,5-dimethyl-3-thienyl)perfluorocyclopentene in crystal and stability of the closed-ring forms in the open-ring forms

Two closed-ring isomers of DMTF in the open-ring crystal were separately observed by Raman spectroscopy. The stability of the two isomers was investigated by quantum chemistry calculations.