...
  • 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 >Threshold collision-induced dissociation and theoretical studies of hydrated Fe(II): Binding energies and coulombic barrier heights
【24h】

Threshold collision-induced dissociation and theoretical studies of hydrated Fe(II): Binding energies and coulombic barrier heights

机译：阈值碰撞诱导的离解和水合Fe（II）的理论研究：结合能和库仑势垒高度

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

The first experimentally determined bond dissociation energies for losing water from Fe~(2+)(H_2O)_n complexes, n = 4-11, are measured using threshold collision-induced dissociation (TCID) in a guided ion beam tandem mass spectrometer coupled to an electrospray ionization source that forms thermalized complexes. In this technique, absolute cross-sections for dissociation induced by collisions with Xe at systematically varied kinetic energies are obtained. After accounting for multiple collisions, kinetic shifts, and energy distributions, these cross-sections are analyzed to yield the energy thresholds for losing one, two, or three water ligands at 0 K. The 0 K threshold measurements are converted to 298 K values to give the hydration enthalpies and free energies for sequentially losing water ligands from each complex. Comparisons to previous results for hydration of Zn~(2+) indicate that the bond energies are dominated by electrostatic interactions, with no obvious variations associated with the open shell of Fe~(2+). Theoretical geometry optimizations and single-point energy calculations are performed using several levels of theory for comparison to experiment, with generally good agreement. In addition to water loss channels, the charge separation process generating hydrated FeOH~+ and protons is observed for multiple reactant complexes. Energies of the rate-limiting transition states are calculated at several levels of theory with density functional approaches (B3LYP and B3P86) disagreeing with MP2(full) results. Comparisons to our kinetic energy dependent cross-sections suggest that the energetics of the MP2(full) level are most accurate.
机译：通过阈值碰撞诱导解离（TCID）在耦合至离子束的串联质谱仪中测量了从Fe〜（2 +）（H_2O）_n配合物中失水的第一个实验确定的键解离能，n = 4-11形成热配合物的电喷雾电离源。在该技术中，获得了在系统变化的动能下与Xe碰撞引起的离解的绝对截面。考虑到多次碰撞，动力学位移和能量分布后，将对这些横截面进行分析，以得出在0 K时失去一，二或三个水配体的能量阈值。将0 K阈值的测量值转换为298 K值给出水合焓和自由能，以使各配合物依次失去水配体。与以前的Zn〜（2+）水合结果的比较表明，键能主要受静电作用的影响，与Fe〜（2+）的开壳没有明显的变化。理论上的几何优化和单点能量计算是使用几种理论水平进行的，可与实验进行比较，总体上吻合良好。除失水通道外，对于多种反应物配合物，还观察到电荷分离过程产生水合FeOH〜+和质子。速率限制过渡态的能量是在理论的几个级别上使用密度泛函方法（B3LYP和B3P86）计算出来的，与MP2（完全）结果不一致。与我们的动能相关截面的比较表明，MP2（full）能级的能量学最准确。

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