Instrumentation for photocrystallographic experiments of transient species.
Instrumentation for photocrystallographic experiments of transient species.
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用于瞬态物种光晶体学实验的仪器。
DOI：
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发表时间：
2000
影响因子：
2.5
通讯作者：
P. Coppens
中科院分区：
文献类型：
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作者：
W. Fullagar;G. Wu;C. Kim;L. Ribaud;G. Sagerman;P. Coppens
描述了低温下频闪时间分辨衍射研究的仪器。激发激光通过光纤传送到晶体。在衍射实验期间，来自样品的荧光被聚焦到激光光纤周围的光纤束上，并由光电二极管监测。旋转的开槽盘产生脉冲 X 射线束，其脉冲频率适合研究寿命为 10 微米或更长的分子激发态。激光泵/X 射线探头脉冲的同步是通过来自安装在旋转盘上的光电传感器或插入光束挡板中的 X 射线敏感光电二极管的触发信号来实现的。对于寿命较短的物种的研究，将使用同步加速器光束的时间结构。导出了最大和平均分数激发态布居数作为寿命、脉冲频率和被激光脉冲激发的分子分数的函数的方程。
Instrumentation for stroboscopic time-resolved diffraction studies at low temperatures is described. Exciting laser light is delivered to the crystal through an optical fiber. During the diffraction experiment, fluorescence from the sample is focused onto a fiber optic bundle surrounding the laser-light fiber, and monitored by a photodiode. A rotating slotted disk produces a pulsed X-ray beam with pulse frequencies suitable for the study of molecular excited states with lifetimes of 10 micros or longer. Synchronization of the laser-pump/X-ray-probe pulses is achieved through a trigger signal from a photosensor mounted on the rotating disk, or from an X-ray sensitive photodiode inserted in the beamstop. For the study of shorter-lived species the time structure of the synchrotron beam is to be used. Equations are derived for the maximum and average fractional excited-state populations as a function of lifetime, pulse frequency and the fraction of molecules being excited by the laser pulse.