Ultrafast ring opening reaction of a photochromic indolyl-fulgimide

• DOI: 10.1016/j.cplett.2005.10.024
• Publication Date: 2005-10-28T11:22:30Z
• Authors: S. Malkmus; F.O. Koller; B. Heinz; W.J. Schreier; T.E. Schrader; W. Zinth; C. Schulz; S. Dietrich; K. Rück-Braun; M. Braun
• Keywords: Picosecond; Exponential decay

Abstract The photo-induced ring-opening reaction C → E of a photochromic indolyl-fulgimide is investigated by sub-picosecond pump–probe spectroscopy in the visible and infrared spectral range. The thermally stable C-isomer shows a pronounced absorption in the visible spectral range without spectral overlap with the absorption of the E- and Z-isomer. The comparison of infrared and visible transient absorption data allows to assign the observed exponential 2.1 ps dynamics to the ring-opening reaction and the non-exponential 10–40 ps component to the cooling of the hot molecules. The transient absorption spectra taken 80 ps after photo-excitation are identical with the steady state difference spectra.