Ultrafast photodissociation dynamics of a hexaarylbiimidazole derivative with pyrenyl groups: dispersive reaction from femtosecond to 10 ns time regions.
The photodissociation dynamics of a hexaarylbiimidazole (HABI) derivative with two pyrenyl groups was investigated by time-resolved transient absorption spectroscopy and fluorescence measurements. Transient absorption spectroscopy revealed that photodissociation took place in the wide time region of <100 fs to 10 ns. On the other hand, fluorescence time profiles showed the dynamic red shift in the time region <100 ps. The apparent dispersive photodissociation process was attributed to the increase in the interaction between the pyrenyl moiety in the excited state and the other moiety in the ground state, resulting in the gradual increase of the activation energy for the crossing between the attractive potential surface of an excited pyrenyl unit and the repulsive potential surface.
Division of Frontier Materials Science, Graduate School of Engineering Science and Center for Quantum Science and Technology under Extreme Conditions, Osaka University, Toyonaka, and CREST, JST, Osaka 560-8531, Japan. miyasaka@chem.es.oska-u.ac.jp
Hiroshi
H
Miyasaka
Yusuke
Y
Satoh
Yukihide
Y
Ishibashi
Syoji
S
Ito
Yutaka
Y
Nagasawa
Seiji
S
Taniguchi
Haik
H
Chosrowjan
Noboru
N
Mataga
Daisuke
D
Kato
Azusa
A
Kikuchi
Jiro
J
Abe