完整的活性空间的数值分析扩展了库普曼斯定理
Reza Hemmati1,2, Mohammad Mostafanejad1,2, J V Ortiz3
1Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, USA.
The Journal of chemical physics
|September 3, 2024
概括
扩展的库普曼定理 (EKT) 准确地预测了完全配置交互 (FCI) 系统的电离能 (IE). 然而,CAS-CI EKT IEs显示复杂的融合,特别是对于像LiH这样的分子,需要仔细选择基础集.
科学领域:
- 量子化学 是一个量子化学.
- 计算化学计算化学
背景情况:
- 扩展的库普曼定理 (EKT) 是计算电离能量的方法.
- 准确的IE计算对于理解原子和分子电子结构至关重要.
研究的目的:
- 评估EKT的数值准确性,用于复制FCI和CAS-CI电离能.
- 为了研究 EKT IEs 的融合行为,具有不同的基础集和活跃空间大小.
主要方法:
- 使用EKT计算原子和分子系统的电离能.
- 将EKT结果与FCI和CAS-CI参考值进行比较.
- 分析了基数大小和扩散函数对EKT精度的影响.
主要成果:
- FCI EKT IEs在增加基准集大小的同时显示出对精确值的趋同.
- CAS-CI EKT IEs不会在更大的基础集或活跃空间下持续改进.
- 正如Davidson等人所指出的那样,使用扩散函数可以系统地改进FCI EKT IEs.
结论:
- 对于精确的IE计算,EKT是有前途的,特别是对于FCI系统.
- CAS-CI EKT IEs的准确性是敏感的基础设置选择和活动空间定义.
- 为了在分子光谱学中准确地预测CAS-CI EKT IE,需要对扩散功能的优化进行进一步的研究.
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