Trap-Seeking or Trap-Digging? Photoinjection of Hydrated Electrons into Aqueous NaCl Solutions
Trap-Seeking or Trap-Digging? Photoinjection of Hydrated Electrons into Aqueous NaCl Solutions
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寻找陷阱还是挖掘陷阱？
DOI：
10.1021/acs.jpclett.2c02243
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Schwartz, Benjamin J.
中科院分区：
文献类型：
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作者：
Narvaez, Wilberth A.;Wu, Eric C.;Park, Sanghyun J.;Gomez, Mariah;Schwartz, Benjamin J.
众所周知，当过量的电子被注入水溶液中时，它们在0.1ps内定位和溶解。仍有争议的是，是否通过“陷阱挖掘”，其中电子雕刻出一个合适的本地化网站，或通过“陷阱搜索”，其中电子更喜欢本地化在预先存在的低能量陷阱网站在解决方案中发生本地化。为了区分这两种可能的机制，我们使用超快光谱和混合量子经典分子动力学模拟研究了NaCl水溶液中过量电子的局域化动力学。通过以Na+离子的形式引入预先存在的陷阱，我们可以使用阳离子诱导的水合电子吸收光谱的蓝移来直接监测电子定位的位置。我们的实验和计算结果表明，电子更倾向于直接定位在Na+陷阱的网站，否则存在的浓缩电解质的方式陷阱寻求水合电子放松注射后的影响不大。
It is well-known that when excess electrons are injected into an aqueous solution, they localize and solvate in ∼1 ps. Still debated is whether localization occurs via “trap-digging”, in which the electron carves out a suitable localization site, or by “trap-seeking”, where the electron prefers to localize at pre-existing low-energy trap sites in solution. To distinguish between these two possible mechanisms, we study the localization dynamics of excess electrons in aqueous NaCl solutions using both ultrafast spectroscopy and mixed quantum-classical molecular dynamics simulations. By introducing pre-existing traps in the form of Na+ions, we can use the cation-induced blue-shift of the hydrated electron’s absorption spectrum to directly monitor the site of electron localization. Our experimental and computational results show that the electron prefers to localize directly at the sites of Na+traps; the presence of concentrated electrolytes otherwise has little impact on the way trap-seeking hydrated electrons relax following injection.