...
  • 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, C. Nanomaterials and interfaces >Structure of the Hydroxyl Groups and Adsorbed D2O Sites in the DX Zeolite: DFT and Experimental NMR Data
【24h】

Structure of the Hydroxyl Groups and Adsorbed D2O Sites in the DX Zeolite: DFT and Experimental NMR Data

机译：DX沸石中羟基基团和吸附的D2O部位的结构：DFT和实验NMR数据

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 report on density functional theory computations combined with the results of measurements of the quadrupole coupling constants for O-17, hydroxyl deuterons, and adsorbed water deuterons in DX zeolite (n(Si)(Al) = 1). Calculations are performed for the crystalline periodic model of the DX zeolite. The local structural parameters are found for various oxygen positions at equilibrium. The quadrupole coupling constants for 170 are in the range C-Q(O-17) = 7.75 +/- 0.5 and 3.75 +/- 0.5 MHz for (Si- OD Al) and (Si-O-Al) substructures, respectively. Related values of the asymmetry parameter eta fall in the ranges of 0.9 +/- 0.5 and 0.15 +/- 0.1, respectively. The quadrupole coupling constant for deuterons depends on the OD distance according to the relation C-Q(D)[MHz] = -2.732d(OD)[MHz/angstrom] + 2.938 MHz. Deuterons are assigned to labeled oxygen positions according to the decreasinng quadrupole coupling constant C-Q(D) as O1 >= O4 >= O2 >= O3, with their relative abundances of 54.4, 7.6, 26.6, and 11.4%, respectively. The binding energy of deuteron in hydroxyl groups and for adsorbed water molecules is analyzed. Formation of the water hexamer in the plane of the 12-ring window was confirmed. Results of the calculations are compared with NMR experimental data for O-17 and D.
机译：我们报告了密度泛函理论的计算结果，并结合了DX沸石（n（Si）/ n（Al）= 1）中O-17，羟基氘核和吸附水氘核的四极耦合常数的测量结果。对DX沸石的结晶周期模型进行计算。找到了处于平衡状态下各个氧位置的局部结构参数。对于（Si-OD Al）和（Si-O-Al）子结构，170的四极耦合常数分别在C-Q（O-17）= 7.75 +/- 0.5和3.75 +/- 0.5 MHz范围内。不对称参数eta的相关值分别落在0.9 +/- 0.5和0.15 +/- 0.1的范围内。氘核的四极耦合常数取决于OD距离，其关系为C-Q（D）[MHz] = -2.732d（OD）[MHz /埃] + 2.938 MHz。根据递减的四极偶合常数C-Q（D），将氘代分配给标记的氧位置，即O1> = O4> = O2> = O3，它们的相对丰度分别为54.4％，7.6、26.6和11.4％。分析了氘核在羟基中和对水分子的结合能。确认了在六环窗平面内形成了六聚体水。将计算结果与O-17和D的NMR实验数据进行比较。

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