Excited-state relaxation properties of ionic and nonionic donor-acceptor biphenyl derivatives

被引：36

作者：

Rettig, W

Kharlanov, V

Maus, M

机构：

[1] Humboldt Univ, Inst Theoret & Phys Chem, D-10117 Berlin, Germany

[2] Rostov Don State Univ, Inst Phys & Organ Chem, Rostov 344104, Russia

来源：

CHEMICAL PHYSICS LETTERS | 2000年 / 318卷 / 1-3期

关键词：

D O I：

10.1016/S0009-2614(99)01444-X

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：

A cationic and a neutral donor-acceptor biphenyl-type system are compared with respect to their photophysical properties. The strong intramolecular fluorescence quenching observed only for the ionic system can be traced back to an excited state twisting relaxation. This process is suppressed either by chemical bridging or by rigidizing the environment at low temperatures. Quantum chemical calculations indicate a strongly different shape of the excited state potential energy surface for the ionic compound, namely a barrierless intramolecular twisting towards perpendicularity, and a significant narrowing of the S-1-S-0 energy gap upon twisting relaxation in the excited state. This suggests a close-lying conical intersection in the ionic case and explains the strongly different fluorescence behaviour of the two compounds. (C) 2000 Elsevier Science B.V. All rights reserved.

引用

页码：173 / 180

页数：8

共 36 条

[1] Photophysics of 4-dimethylamino 4'-cyanostilbene and model compounds: Dual excited states revealed by sub-picosecond transient absorption and Kerr ellipsometry [J].