Charge-transfer-to-solvent reactions from I- to water, methanol, and ethanol studied by time-resolved photoelectron spectroscopy of liquids
Charge-transfer-to-solvent reactions from I- to water, methanol, and ethanol studied by time-resolved photoelectron spectroscopy of liquids
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DOI：
10.1063/1.4960385
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发表时间：
2016-08-21
影响因子：
4.4
通讯作者：
Suzuki, Toshinori
中科院分区：
文献类型：
--
作者：
Okuyama, Haruki;Suzuki, Yoshi-Ichi;Suzuki, Toshinori
使用具有可变通过能量的磁瓶飞行时间光谱仪，通过液体微射流的时间分辨光电子能谱研究了从碘化物 (I-) 到 H2O、D2O、甲醇和乙醇的电荷转移到溶剂 (CTTS) 反应。光激发的碘化物在相似的反应时间内解离成溶剂化电子和碘原子的弱络合物（接触对），在H2O和D2O中为0.3 ps，在甲醇和乙醇中为0.5 ps，这比它们的介电弛豫时间短得多。结果表明，在 I- 产生的长程溶剂极化场中，溶剂化电子的形成只需极少的溶剂重组。 H2O 和 D2O 中 CTTS 的光电子能谱测量精度比我们之前的研究 [Y. I.铃木等人，化学。科学。 2, 1094 (2011)]-表明光激发 I-* (CTTS) 态的内转化产率低于 10%，而醇提供的 I-* 内转化产率高 2-3 倍。发现总的孪生重组产率的顺序为H2O>D2O>甲醇>乙醇，这与碘原子和溶剂化电子的相互扩散速率的顺序相反。该结果与绝热外层电子转移过程的过渡态理论一致，该理论预测复合反应速率具有与纵向溶剂弛豫时间成反比的指前因子。由 AIP 出版社出版。
The charge-transfer-to-solvent (CTTS) reactions from iodide (I-) to H2O, D2O, methanol, and ethanol were studied by time-resolved photoelectron spectroscopy of liquid microjets using a magnetic bottle time-of-flight spectrometer with variable pass energy. Photoexcited iodide dissociates into a weak complex (a contact pair) of a solvated electron and an iodine atom in similar reaction times, 0.3 ps in H2O and D2O and 0.5 ps in methanol and ethanol, which are much shorter than their dielectric relaxation times. The results indicate that solvated electrons are formed with minimal solvent reorganization in the long-range solvent polarization field created for I-. The photoelectron spectra for CTTS in H2O and D2O-measured with higher accuracy than in our previous study [Y. I. Suzuki et al., Chem. Sci. 2, 1094 (2011)]-indicate that internal conversion yields from the photoexcited I-* (CTTS) state are less than 10%, while alcohols provide 2-3 times greater yields of internal conversion from I-*. The overall geminate recombination yields are found to be in the order of H2O > D2O > methanol > ethanol, which is opposite to the order of the mutual diffusion rates of an iodine atom and a solvated electron. This result is consistent with the transition state theory for an adiabatic outer-sphere electron transfer process, which predicts that the recombination reaction rate has a pre-exponential factor inversely proportional to a longitudinal solvent relaxation time. Published by AIP Publishing.