Global and target analysis of time-resolved fluorescence spectra of Di-9H-fluoren-9-yldimethylsilane: Dynamics and energetics for intramolecular excimer formation
Global and target analysis of time-resolved fluorescence spectra of Di-9H-fluoren-9-yldimethylsilane: Dynamics and energetics for intramolecular excimer formation
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DOI：
10.1021/jp0406621
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发表时间：
2005-05-19
影响因子：
2.9
通讯作者：
Kang, D
中科院分区：
文献类型：
--
作者：
Boo, BH;Kang, D
用ps时间分辨荧光光谱和从头算方法研究了二芳基硅烷（DFYDMS）分子内激基缔合物形成的动力学和能量学.多个荧光衰减曲线进行全局去卷积，以产生时间分辨的荧光光谱和衰减相关光谱（DAS），从物种相关光谱（SAS）获得。在全局分析中示出，至少存在三个激发态：两个态是具有0.70 +/- 0.04和1.75 +/- 0.02 ns的寿命的局部激发（LE）态（λ（max）类似于320 nm），另一个态是具有7.34 +/- 0.02 ns的寿命的受激准分子态（λ（max）类似于400 nm）。衰变时间为0.70 ns的物质演化为光谱红移的物质，其衰变时间为7.34 us。实验和从头计算结果表明，上升时间为0.70 ns，对应于具有近三明治几何结构的初始S-1 LE态到采用真正三明治几何结构的S-1准分子态的转换。
Dynamics and energetics for intramolecular excimer formation of a diarylsilane, di-9H-fluoren-9-yldimethylsilane (DFYDMS) have been investigated by means of ps time-resolved fluorescence spectroscopy and ab initio calculation. Multiple fluorescence decay curves were globally deconvolved to generate time-resolved fluorescence spectra and decay-associated spectra (DAS), from which species-associated spectra (SAS) were obtained. It is shown in the global analysis that there are at least three excited states: Two states are the locally excited (LE) states (lambda(max) similar to 320 nm) having lifetimes of 0.70 +/- 0.04 and 1.75 +/- 0.02 ns, and another is the excimer state (lambda(max) similar to 400 nm) having a lifetime of 7.34 +/- 0.02 ns. The species which decays with 0.70 ns evolves into a species with a red-shifted spectrum, which in turn decays in 7.34 us. The experimental and ab initio results indicate that the rise time of 0.70 ns corresponds to the conversion of the initial S-1 LE state having a near sandwich geometry to the S-1 excimer state adopting a true sandwich geometry.