论文标题
2- thiouracil中放松动力学的超快照相离子探测
Ultrafast photo-ion probing of the relaxation dynamics in 2-thiouracil
论文作者
论文摘要
在这项工作中，我们通过使用Ultrafast，单色，泵浦探针/紫外线光谱法调查了紫外光激发后2-硫核的松弛过程。我们将重点放在研究电离片段的外观和随后的衰减信号上。我们通过在同步加速器上收集的VUV诱导的脉冲诱导的光电离研究进行补充，从而使我们能够更好地理解和分配片段出现的离子化通道。我们发现，当在VUV实验中使用具有能量> 11 eV的单个光子时，所有片段都会出现，因此，当使用266 nm光时，通过3+光子阶过程出现UV/UV实验。我们还观察到碎片离子的三个主要衰变：亚自动相关衰减（即低370 fs），300-450 fs的次级超快衰减，以及在220至400 ps的阶段（所有片段依赖于）。这些衰变与先前建立的S2-> S1->三重态 - >地面衰减过程非常吻合。 VUV研究的结果还表明，某些片段可能是由于激发阳离子状态上发生的动力学而产生的。关键词：thiouracil;乌拉西尔；泵探针光谱；超快
In this work we investigate the relaxation processes of 2-thiouracil after UV photoexcitation to the S2 state through the use of ultrafast, single-color, pump-probe UV/UV spectroscopy. We place focus on investigating the appearance and subsequent decay signals of ionized fragments. We complement this with VUV-induced disso-ciative photoionization studies collected at a synchrotron, allowing us to better understand and assign the ion-isation channels involved in the appearance of the fragments. We find that all fragments appear when single photons with energy > 11 eV are used in the VUV experiments and hence appear through 3+ photon-order processes when 266 nm light is used the UV/UV experiment. We also observe three major decays for the frag-ment ions: a sub-autocorrelation decay (i.e. sub-370 fs), a secondary ultrafast decay on the order of 300-450 fs, and a long decay on the order of 220 to 400 ps (all fragment dependent). These decays agree well with the previously established S2 -> S1 -> Triplet -> Ground decay process. Results from the VUV study also suggest that some of the fragments may be created by dynamics occurring on the excited cationic state. Keywords: thiouracil; uracil; pump-probe spectroscopy; ultrafast
