Excited triplet states used to study biological macromolecules at room temperature.
Excited triplet states used to study biological macromolecules at room temperature.
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激发三重态用于在室温下研究生物大分子。
DOI：
10.1016/s0005-2728(89)80185-9
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
Berger,JW
中科院分区：
文献类型：
--
作者：
Vanderkooi,JM;Berger,JW
荧光和磷光是吸收光之后的发射过程。虽然从古代起就已经观察到这两者，但正是在这个世纪，两者之间的区别是基于机制。Jablonski提出，激发态低于初始激发态可以解释分子的多重发射[126]。在20世纪40年代，刘易斯和Kasha确定磷光是从三重激发态发射的光[169]，刘易斯和卡尔文证明了激发三重态中存在未成对电子[168]。这个定义现在被接受：荧光是来自自旋允许跃迁的光发射，而磷光是来自自旋不允许跃迁的光发射。在几乎所有的情况下，荧光表示在从单重激发态到基态的跃迁中发射的光，而磷光是从三重激发态到基态发射的光。磷光发射是红移的，并且比荧光寿命长得多，这些特征用于在实验上区分荧光和磷光。荧光现在是生物分子研究中被广泛接受的工具。激光器和快速计算机驱动的数据采集设备的发展允许以极高的精度测量超短荧光寿命，荧光技术已经解决了有关分子运动，距离，方向和环境的基本问题。
Fluorescence and phosphorescence are emission processes following the absorption of light. Although both have been observed since antiquity, it was in this century that a distinction between the two was made based upon mechanism. Jablonski suggested that an excited state which is lower lying than the initially excited state could explain multiple emission from a molecule [126]. In the 1940's Lewis and Kasha identified phosphorescence as the light emitted from the triplet excited state [169] and Lewis and Calvin demonstrated the existence of unpaired electrons in the excited triplet state [168]. This definition is now accepted: fluorescence is light emission from a spin-allowed transition whereas phosphorescence is light emission from a spin-disallowed transition. In nearly all cases fluorescence represents the light emitted in the transition from the singlet excited state to the ground state, whereas phosphorescence is light emitted from the triplet excited state to the ground state. Phosphorescence emission is red-shifted and is much longer lived than fluorescence and these features serve to distinguish fluorescence and phosphorescence experimentally.Fluorescence is now a widely accepted tool for the study of biological molecules. The development of lasers and fast computer-driven data-acquisition devices allows for the measurement of ultra-short fluorescence lifetimes with great accuracy, and fluorescence techniques have addressed fundamental questions concerning molecular motion, distances, orientation and environment.