Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark.
J Am Soc Mass Spectrom. 2010 Nov;21(11):1884-8. doi: 10.1016/j.jasms.2010.07.004. Epub 2010 Jul 16.
Here we demonstrate that pump-probe experiments can be carried out on microsecond to millisecond timescales using an electrostatic ion storage ring. As a test case, we have chosen protoporhyrin IX anions that have lifetimes with respect to dissociation after photoexcitation on this time scale. Ions were photoexcited on one side of the ring with either 430- or 535-nm light (pump) and then allowed to take a certain number of revolutions before they were photoexcited by a second laser pulse (probe) with wavelengths between 650 and 950 nm. If ions were first excited by the pump, an increased yield of neutral products caused by the absorption of red light was measured in a microchannel plate detector located on the other side of the ring. This implies that it is possible to pick out ions that were photoexcited by the pump pulse and to spectroscopically characterize these ions. We report absorption spectra of 535 nm photoexcited porphyrin anions, with time delays of 0.19 and 0.57 ms between the pump and probe pulses, and find that absorption occurs over a broad region in the red.
在这里，我们展示了可以在微秒到毫秒的时间尺度上使用静电离子储存环进行泵浦-探测实验。作为一个测试案例，我们选择了原卟啉 IX 阴离子，它们在光激发后的解离寿命在这个时间尺度上。离子在环的一侧用 430nm 或 535nm 光（泵浦）进行光激发，然后让它们旋转一定数量的圈数，然后用波长在 650nm 到 950nm 之间的第二激光脉冲（探测）进行光激发。如果离子首先被泵浦激发，在位于环另一侧的微通道板探测器中测量到由红光吸收引起的中性产物的增加产量。这意味着可以挑选出被泵浦脉冲光激发的离子，并对这些离子进行光谱表征。我们报告了在 535nm 光激发卟啉阴离子的吸收光谱，泵浦和探测脉冲之间的时间延迟为 0.19ms 和 0.57ms，发现吸收发生在红色的宽区域内。
