• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Ultrafast Dynamics of the Excited States of the Uranyl Ion in Solutions
【24h】

Ultrafast Dynamics of the Excited States of the Uranyl Ion in Solutions

机译：溶液中铀酰离子激发态的超快动力学

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

We have investigated the relaxation dynamics of the higher excited states of the uranyl ion in aqueous and methanolic solutions following photoexcitation to the S1(1Φg) state using 400 nm light. Although the timeresolved spectra are significantly different in these two solvents, the temporal dynamics studied in the entire wavelength region clearly suggest the involvement of three excited state processes in both solvents. The S1(1Φg) state undergoes ultrafast intersystem crossing (τISC<100 fs) to the higher vibrational levels of the T2(3Δg) state, followed by the intramolecular vibrational relaxation (IVR) process in the later electronic state (τIVR 0.85 and 1 ps in aqueous and methanolic solutions, respectively). Subsequently, the T2(3Δg) state undergoes an internal conversion (IC) process (τIC l.6 and 4.5 ps in aqueous and methanol solutions, respectively) to the long-lived T1(3Φg) state, which is responsible for the luminescent properties of the uranyl ion. In neat methanol, because of stronger interaction between the excited triplet, T1(3Φg), state and the solvent via solvent to uranyl charge transfer, the U(VI) ion undergoes partial reduction to U(V) and the energy level of this state possibly lies lower than that of (UO2 2+)*, which is the transient species existing in aqueous solution, and hence increasing the energy gap between the T2 and T1 states in methanol solution. These facts possibly explain different spectral characteristics of the transient species produced in methanol and aqueous solutions as well as the longer lifetime of the IC process in methanol solution.
机译：我们已经研究了在400 nm光激发下S1（1Φg）激发后，水溶液和甲醇溶液中铀酰离子的高激发态的弛豫动力学。尽管时间分辨光谱在这两种溶剂中显着不同，但在整个波长范围内研究的时间动力学清楚地表明这两种溶剂都涉及三个激发态过程。 S1（1Φg）状态经历超快的系统间穿越（τISC<100 fs）至T2（3Δg）状态的更高振动水平，随后在较晚的电子状态（τIVR0.85和1 ps）发生分子内振动弛豫（IVR）过程分别在水溶液和甲醇溶液中）。随后，T2（3Δg）状态经历内部转换（IC）过程（在水溶液和甲醇溶液中分别为τIC1.6和4.5 ps）到长寿命的T1（3Φg）状态，这是发光特性的原因铀酰离子。在纯甲醇中，由于激发的三重态，T1（3Φg），态与溶剂之间通过溶剂向铀酰的电荷转移，相互作用更强，因此U（VI）离子会部分还原为U（V）和该态的能级可能低于水溶液中存在的瞬态物质（UO2 2 +）*，因此会增加甲醇溶液中T2和T1状态之间的能隙。这些事实可能解释了甲醇和水溶液中产生的瞬态物质的不同光谱特征，以及IC工艺在甲醇溶液中的更长寿命。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号