Intramolecular excimer formation of oligostyrenes from dimer to tridecamer: The measurements of rate constants for excimer formation, singlet energy migration, and relaxation of internal rotation
Intramolecular excimer formation of oligostyrenes from dimer to tridecamer: The measurements of rate constants for excimer formation, singlet energy migration, and relaxation of internal rotation
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低聚苯乙烯从二聚体到十三聚体的分子内准分子形成：准分子形成、单线态能量迁移和内旋转弛豫的速率常数的测量
DOI：
10.1063/1.446269
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发表时间：
1983
影响因子：
4.4
通讯作者：
Y. Tabata
中科院分区：
文献类型：
--
作者：
H. Itagaki;K. Horie;I. Mita;M. Washio;S. Tagawa;Y. Tabata
利用皮秒脉冲辐解技术研究了苯乙烯齐聚物从二聚体到十三聚体的室温辐射性质。低聚物被精确地分级，并被认为是无规立构聚苯乙烯的模型。激基缔合物形成的速率常数kDM约为108 s-1，随着单体单元数n的增加而增加（2≤n≤8），然后在聚苯乙烯的数值处趋于稳定。聚苯乙烯中相邻发色团之间的单重态能量迁移速率常数被确定为3×1010 s−1（1030 ps）。两个相邻的发色团从它们的初始平衡构象分布到呈现激基缔合物构象（外消旋二分体中为g−t或tg−;内消旋二分体中为tt）需要平均7.2 ns的时间。目前的结果是一个迹象表明，人们可以调查动态的内部旋转的物理技术。此外，从光定态测量结果与瞬态方法的比较，它是…
The emission properties of styrene oligomers from dimer to tridecamer have been investigated by picosecond pulse radiolysis at room temperature. The oligomers are precisely fractionated and are considered to be models of atactic polystyrene. The rate constant for excimer formation kDM of the order of 108 s−1, increases with increasing number of monomer units n for 2≤n≤8, then levels off at the value for polystyrene. The rate constant for singlet energy migration between adjacent chromophores in polystyrene was determined to be 3×1010 s−1 (∼30 ps). An average time of 7.2 ns was found to be necessary for two adjacent chromophores to assume the excimer conformation (g−t or tg− in a racemo dyad; tt in a meso dyad) from their initial equilibrium distribution of conformations. The present result is an indication that one may investigate the dynamics of internal rotation by photophysical techniques. Moreover, from a comparison of the results of photostationary measurements with those of transient methods, it is ...