Competition between ultrafast relaxation and photoionization in excited prefluorescent states of tryptophan and indole.
Competition between ultrafast relaxation and photoionization in excited prefluorescent states of tryptophan and indole.
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DOI：
10.1063/1.2348868
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发表时间：
2006-10
期刊：
影响因子：
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通讯作者：
P. Sherin;O. Snytnikova;Y. Tsentalovich;R. Sagdeev
中科院分区：
文献类型：
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作者：
P. Sherin;O. Snytnikova;Y. Tsentalovich;R. Sagdeev
TrpH和IndH从非弛豫预荧光态S* 光电离的量子产率随温度的降低而增加。这种效应归因于与温度无关的电离和超快热弛豫S* -> S1之间的竞争。弛豫的速率常数不依赖于溶剂和氨基酸侧链的存在下：光电离量子产率的温度依赖性，在不同的溶剂中获得的TrpH和IndH，几乎一致。弛豫速率常数Er约为4.5 kJ/mol，其活化能可能对应于分子内过程或光激发分子与溶剂分子之间形成的振动激发瞬态复合物。
The quantum yield of photoionization of TrpH and IndH from the nonrelaxed prefluorescent state S* increases with the temperature decrease. This effect is attributed to the competition between temperature independent ionization and ultrafast thermal relaxation S* --> S1. The rate constant of the relaxation does not depend on the solvent and on the presence of the amino acid side chain: the temperature dependences of photoionization quantum yield, obtained for TrpH and IndH in different solvents, practically coincide. The activation energy for the relaxation rate constant Er approximately 4.5 kJ/mol probably corresponds to intramolecular process or to the formation of the vibronically excited transient complex between photoexcited molecule and solvent molecules.