Femtosecond fluorescence and absorption dynamics of an azobenzene with a strong push-pull substitution

被引：69

作者：

Schmidt, B ^{[1
]}

Sobotta, C ^{[1
]}

Malkmus, S ^{[1
]}

Laimgruber, S ^{[1
]}

Braun, M ^{[1
]}

Zinth, W ^{[1
]}

Gilch, P ^{[1
]}

机构：

[1] Univ Munich, Sekt Phys, D-80538 Munich, Germany

来源：

JOURNAL OF PHYSICAL CHEMISTRY A | 2004年 / 108卷 / 20期

关键词：

D O I：

10.1021/jp0495747

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

The ultrafast photoisomerization of a push-pull substituted azobenzene (4-nitro-4'-(dimethylamino)azobenzene, NA) is studied by means of femtosecond fluorescence and absorption spectroscopy. The fluorescence dynamics is biphasic. The initial fluorescence with a narrow and intense spectrum decays in similar to100 fs. This decay is accompanied by the rise of broad red-shifted and much weaker emission. The same time constants recur in the transient absorption spectra which hold additional information on the ground-state dynamics. The ground state recovers in 0.8 ps, demonstrating that only the longer time constant is associated with an internal conversion process. Small spectral changes occurring thereafter (similar to5 ps) point to vibrational cooling in the ground state. The results are analyzed in comparison with the behavior of the parent compound azobenzene. Though the push-pull substitution of azobenzene strongly alters the character of its excited states, the photodynamics are surprisingly robust with respect to that substitution.

引用

页码：4399 / 4404

页数：6

共 17 条

[1] Ultrafast intramolecular electron transfer from a ferrocene donor moiety to a nile blue acceptor [J].