...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Proceedings of the National Academy of Sciences of the United States of America >Observation of a Zundel-like transition state during proton transfer in aqueous hydroxide solutions
【24h】

Observation of a Zundel-like transition state during proton transfer in aqueous hydroxide solutions

机译：氢氧化物水溶液中质子转移过程中Zundel样过渡态的观察

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

It is generally accepted that the anomalous diffusion of the aqueous hydroxide ion results from its ability to accept a proton from a neighboring water molecule; yet, many questions exist concerning the mechanism for this process. What is the solvation structure of the hydroxide ion? In what way do water hydrogen bond dynamics influence the transfer of a proton to the ion? We present the results of femtosecond pump-probe and 2D infrared experiments that probe the O-H stretching vibration of a solution of dilute HOD dissolved in NaOD/D_2O. Upon the addition of NaOD, measured pump-probe transients and 2D IR spectra show a new feature that decays with a 110-fs time scale. The calculation of 2D IR spectra from an empirical valence bond molecular dynamics simulation of a single NaOH molecule in a bath of H_2O indicates that this fast feature is due to an overtone transition of Zundel-like H_3O_2~- states, wherein a proton is significantly shared between a water molecule and the hydroxide ion. Given the frequency of vibration of shared protons, the observations indicate the shared proton state persists for 2-3 vibrational periods before the proton localizes on a hydroxide. Calculations based on the EVB-MD model argue that the collective electric field in the proton transfer direction is the appropriate coordinate to describe the creation and relaxation of these Zundel-like transition states.
机译：通常认为氢氧根离子的反常扩散是由于其接受来自邻近水分子的质子的能力所致；因此，氢氧根离子的异常扩散是由于其接受质子的能力。但是，有关此过程的机制存在许多问题。氢氧根离子的溶剂化结构是什么？水氢键动力学以何种方式影响质子向离子的转移？我们提出了飞秒泵浦探针和2D红外实验的结果，该实验探测了溶解在NaOD / D_2O中的稀HOD溶液的O-H拉伸振动。添加NaOD后，测得的泵浦探针瞬变和2D IR光谱显示出一个新特征，该特征会在110 fs的时间范围内衰减。从H_2O浴中单个NaOH分子的经验价键分子动力学模拟计算2D IR光谱表明，该快速特征是由于Zundel样H_3O_2〜-态的泛音跃迁所致，其中质子显着共享在水分子和氢氧根离子之间。给定共享质子的振动频率，观察表明共享质子状态在质子定位于氢氧化物之前会持续2-3个振动周期。基于EVB-MD模型的计算认为，质子传递方向的集体电场是描述这些Zundel状过渡态的产生和弛豫的合适坐标。

著录项

  • 来源
  • 作者

    Sean T. Roberts; Poul B. Petersen; Krupa Ramasesha; Andrei Tokmakoff; Ivan S. Ufimtsev; Todd J. Martinez;

  • 作者单位

    Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139;

    Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139;

    Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139;

    Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139;

    Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801 Department of Chemistry, Stanford University, Stanford, CA 94305;

    Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801 Department of Chemistry, Stanford University, Stanford, CA 94305;

  • 收录信息 美国《科学引文索引》(SCI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    grotthuss mechanism; 2D infrared spectroscopy;

    机译：格罗特斯机制二维红外光谱;

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