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Indexed by:期刊论文

Date of Publication:2010-12-01

Journal:CHINESE JOURNAL OF CHEMICAL PHYSICS

Included Journals:SCIE、CSCD、Scopus

Volume:23

Issue:6

Page Number:637-642

ISSN No.:1674-0068

Key Words:Volume-conserved twisted state; Time-resolved photon emission; Photoisomerization

Abstract:The excited state characters of HY103 have been studied by means of time-resolved photon emission (time-correlated single photon counting) and time dependent density functional theory calculations. The experimental and theoretical results demonstrate that HY103 dyes undergo an efficient one-bond-flip motion after photoexicitation at room temperature, which leads to a very short lifetime of the normal fluorescence state, and a weak fluorescence emission around 670 rim. However, when HY103 are excited in amorphous glasses at 77 K, the normal fluorescence emission is prolonged to nanoseconds time scale about 2 us, and the fluorescence emission is enhanced. Furthermore, a new emission state is produced, which is characterized as a volume-conserved twisted (VCT) state. This is the first observation of a VCT state. The experiment indicates that the VCT motion of excited state of pi-conjugated molecules in restricted environment can form a stable emission state, and the excited state character of pi-conjugated molecules in restricted environment is complex.