精确的热化学与多引用方法:一个压力测试内部合同的多引用合集群理论
Alexander Waigum1, Murat Ertürk2, Andreas Köhn1
1Institute for Theoretical Chemistry, University of Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany.
The journal of physical chemistry. A
|November 13, 2024
概括
内部合同的多引用合集群方法与单,双和扰动三次激发 (icMRCCSD(T)) 已被改进为高精度热化学. 新的icMRCCSD(cT*) F方法在双核化合物和过渡金属化物方面取得了非常准确的结果.
科学领域:
- 计算化学计算化学
- 量子化学 是一个量子化学.
- 理论化学 理论化学
背景情况:
- 内部合同的多引用合集群方法,单,双和扰动三次激发 (icMRCCSD(T)) 是高精度热化学的关键工具.
- 现有的icMRCCSD (T) 公式面临着特定的哈密尔顿式和高估扰动性校正的挑战,特别是对于有开放外的系统.
研究的目的:
- 评估和改进 icMRCCSD (T) 计算高精度热化学方法的性能.
- 解决当前icMRCCSD(T) 公式中发现的局限性,特别是关于选择零次哈密尔顿方程和振幅方程.
主要方法:
- 对第一排二核化合物和3d过渡金属化物 (MnH,FeH,CoH) 的标准单参考合集群方法进行了icMRCCSD(T) 方法的测试.
- 研究了使用戴尔哈密尔顿式与有效的福克运算子作为零阶哈密尔顿式的使用.
- 实施了修改后的振幅方程,称为"cT*) 校正",以解释对集群中的二次式项,灵感来自最近对单参考合集群理论的研究.
主要成果:
- 识别了标准icMRCCSD(T的两个主要问题:来自迪亚尔哈密尔顿式的偏向描述和扰动性三重刺激的高估.
- 改进的icMRCCSD ((cT*) F方法,利用有效的福克运算符和 (cT*) 校正,显著提高了准确性.
- 改进的方法在测试的化合物中实现了总和原子化能低于2kJ/mol的误差,超过了以前的基准.
结论:
- 修改后的icMRCCSD(cT*) F方法为计算热化学提供了强大的,高度准确的方法,特别是对于具有挑战性的系统,如过渡金属化合物.
- 有效的福克运算符和 (cT*) 校正对于解决标准icMRCCSD (T) 公式的局限性至关重要.
- 这一进步为研究分子能量学的理论化学家提供了更可靠的工具.
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