旋转翻转运动方程合集群方法,单,双和 (完全) 三倍:计算实现和一些试点应用程序
Manisha1, Prashant Uday Manohar1
1Department of Chemistry, Birla Institute of Technology & Science-Pilani, Pilani, Rajasthan 333031, India. pumanohar@pilani.bits-pilani.ac.in.
Physical chemistry chemical physics : PCCP
|July 29, 2024
概括
我们开发了一种新的计算方法,旋转翻转运动方程合集群与单,双和三重 (SF-EOM-CCSDT),用于准确的电子结构计算. 这种方法提高了能量差距和激发能量的精度,即使是单一精度,也可以研究更大的分子.
科学领域:
- 计算化学的计算化学
- 量子化学 是一个量子化学.
- 理论化学 理论化学
背景情况:
- 精确计算电子结构对于理解分子性质至关重要.
- 现有的方法,如SF-EOM-CCSD,对于某些系统可能缺乏定量准确性.
- 已知包括三次激发可以提高合集群方法的准确性.
研究的目的:
- 在计算上实现旋转翻转运动方程合集群方法,使用单元,双元和全三元 (SF-EOM-CCSDT).
- 评估SF-EOM-CCSDT方法的准确性和适用性.
- 为了研究双精度 (DP) 和单精度 (SP) 算法的性能.
主要方法:
- 在Q-CHEM计算化学包中实施SF-EOM-CCSDT.
- 将SF-EOM-CCSDT结果与基准方法进行比较:完整配置交互 (FCI) 和完整活动空间自相一致的第二阶段场 (CASSCF-SO) CI.
- 应用用于研究二极极子 (CH2,NH2+),垂直激发能 (CH极子) 和键解离 (HF) 中的亚底波能量差距.
主要成果:
- 包含三倍数显著提高了SF-EOM-CCSD的定量准确性,为退化状态之间的能源差距提供了正确的定性趋势.
- SF-EOM-CCSDT的结果与研究系统的FCI和CASSCF-SO基准值达成良好一致.
- 与双精度 (DP) 相比,SF-EOM-CCSDT的单精度 (SP) 实现产生了精确的能量和能量差距,并降低了计算成本.
结论:
- SF-EOM-CCSDT是一种高精度的方法,用于计算电子激发能量和能量差距.
- SF-EOM-CCSDT的SP实现提供了一个计算高效的方法,扩大其适用于更大的分子系统.
- 这项工作为研究复杂电子结构和反应动态的理论化学家提供了宝贵的工具.
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