• 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 >Adsorption of water molecules on selected charged sodium-chloride clusters
【24h】

Adsorption of water molecules on selected charged sodium-chloride clusters

机译：水分子在选定的带电氯化钠簇上的吸附

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 adsorption of water molecules (H _2O) on sodium chloride cluster cations and anions was studied at 298 K over a mass range of 100-1200 amu using a custom-built laser desorption ionization reactor and mass spectrometer. Under the conditions used, the cations Na _3Cl _2 ~+ and Na _4Cl _3 ~+ bind up to three water molecules, whereas the larger cations, Na _5Cl _4 ~+ to Na _(19)Cl _(18) ~+, formed hydrates with one or two only. The overall trend is a decrease in hydration with increasing cluster size, with an abrupt drop occurring at the closed-shell Na _(14)Cl _(13) ~+. As compared to the cluster cations, the cluster anions showed almost no adsorption. Among smaller clusters, a weak adsorption of one water molecule was observed for the cluster anions Na _6Cl _7 - and Na _7Cl _8 -. In the higher mass region, a substantial adsorption of one water molecule was observed for Na _(14)Cl _(15) -. Density functional theory (DFT) computations were carried out for the adsorption of one molecule of H _2O on the cations Na _nCl _(n-1) ~+, for n = 2-8, and the anions Na _nCl _(n+1) -, for n = 1-7. For each ion, the structure of the hydrate, the hydration energy, and the standard-state enthalpy, entropy, and Gibbs energy of hydration at 298 K were computed. In addition, it was useful to compute the distortion energy, defined as the electronic energy lost due to weakening of the Na-Cl bonds upon adsorption of H _2O. The results show that strong adsorption of a H _2O molecule occurs for the linear cations only at an end Na ion and for the nonlinear cations only at a corner Na ion bonded to two Cl ions. An unexpected result of the theoretical investigation for the anions is that certain low-energy isomers of Na _6Cl _7 - and Na _7Cl _8 - bind H _2O strongly enough to produce the observed weak adsorption. The possible implications of these results for the initial hydration of extended NaCl surfaces are discussed.
机译：使用定制的激光解吸电离反应器和质谱仪，研究了在298 K下100-1200 amu的质量范围内水分子（H _2O）在氯化钠簇状阳离子和阴离子上的吸附。在所使用的条件下，阳离子Na _3Cl _2〜+和Na _4Cl _3〜+最多结合三个水分子，而较大的阳离子Na _5Cl _4〜+形成Na_（19）Cl _（18）〜+。只能与一两个水合。总体趋势是随着团簇尺寸的增加，水合作用减少，在闭壳Na _（14）Cl _（13）〜+处急剧下降。与簇状阳离子相比，簇状阴离子几乎没有吸附。在较小的簇中，对于簇阴离子Na _6Cl _7-和Na _7Cl _8-，观察到一个水分子的弱吸附。在较高质量的区域中，Na _（14）Cl _（15）-基本上观察到一个水分子的吸附。进行密度泛函理论（DFT）计算，以将一分子H _2O吸附在阳离子Na _nCl _（n-1）〜+上（n = 2-8）和阴离子Na _nCl _（n + 1）上）-，n = 1-7。对于每个离子，计算了298 K时的水合物结构，水合能，标准态焓，熵和Gibbs水合能。另外，计算畸变能是有用的，该畸变能定义为由于吸附H _2O时Na-Cl键变弱而损失的电子能。结果表明，仅在末端Na离子上的线性阳离子和仅在结合两个Cl离子的角Na离子上的非线性阳离子发生H _2O分子的强吸附。对阴离子进行理论研究的一个出乎意料的结果是，Na _6Cl _7-和Na _7Cl _8-的某些低能异构体与H _2O的结合强度足以产生弱的吸附。讨论了这些结果对扩展NaCl表面初始水合的可能含义。

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