首页> 外文学位 >Application of computational quantum chemistry to problems in chemistry and spectroscopy.
【24h】

Application of computational quantum chemistry to problems in chemistry and spectroscopy.

机译:计算量子化学在化学和光谱学问题中的应用。

获取原文
获取原文并翻译 | 示例

摘要

A wide variety of commonly implemented computational practices were examined to evaluate their feasibility as well as their accuracy. In terms of theoretical inorganic chemistry, it was found that for systems of small to moderate size that MP2 is the method of choice. There is no justification for using B3LYP or any other DFT method with basis sets that have a pseudopotential. B3LYP outperforms MP2 in terms of computational cost only on very large systems because of the integration grid. The common practice of ligand substitution for the purpose of computational feasibility (i.e. replace PtBu2Me with PH3) can have a dramatic impact upon computed energies since the replacement ligand will have not only different steric effects, but also very different electron effects. This is most evident in reactions where the formal oxidation charge on the metal center changes. In terms of applications to spectroscopy, the electronic spectrum of CuCl was computed and the PES of its trimer (D3h symmetry) was computed. The electronic energies of CuCl are computed much more accurately and in better agreement with experiment than with previous lower level work. The PES calculation was used to make an assignment of experimentally observed PES peaks. Finally, the method of DFT was coded into the program MELD for future research work.
机译:检查了各种常用的计算实践,以评估其可行性和准确性。在理论无机化学方面,发现对于中小尺寸的系统,MP2是首选方法。没有理由将B3LYP或任何其他DFT方法与具有伪电位的基集一起使用。由于集成网格的原因,B3LYP在计算成本方面仅胜过MP2。为了计算可行性(即用PH3代替PtBu2Me),配体取代的常见做法可能对计算出的能量产生巨大影响,因为取代的配体不仅具有不同的空间效应,而且还具有非常不同的电子效应。这在金属中心的形式氧化电荷发生变化的反应中最为明显。根据光谱学的应用,计算了CuCl的电子光谱,并计算了其三聚体的PES(D3h对称性)。与以前的较低水平的工作相比,CuCl的电子能计算得更加准确,并且与实验更好地吻合。 PES计算用于指定实验观察到的PES峰。最后,将DFT的方法编码到程序MELD中,以备将来研究之用。

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