Excitation relaxation of zinc and free-base porphyrin probed by femtosecond fluorescence spectroscopy

• Published in: Chemical physics letters Vol. 309; no. 3; pp. 177 - 182
• Main Authors: Akimoto, Seiji, Yamazaki, Tomoko, Yamazaki, Iwao, Osuka, Atsuhiro
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 13.08.1999
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/S0009-2614(99)00688-0

Fluorescence rise and decay times of zinc porphyrin (ZnP) and free-base porphyrin (H 2P) were measured using a fluorescence up-conversion method. The observed fluorescence signals were analyzed to be a sum of three exponentials: 150 fs, 600 fs, and 1.5 ns for ZnP; and 90 fs, 1.5 ps, and 12 ns for H 2P. The two fastest components of 150 and 600 fs for ZnP are associated with the decay processes of B→Q internal conversion and the vibrational relaxation in the Q state, respectively. The short-lived components of 90 fs and 1.5 ps for H 2P are correlated with the decay processes of Q y →Q x internal conversion and the vibrational relaxation in the Q x state, respectively.