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arXiv 2203.09491physics.chem-ph
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在相似变换EOM理论中纳入芯三重激发以获得精确的芯激发态

Accurate core-excited states via inclusion of core triple excitations in similarity-transformed EOM theory

Megan Simons, Devin A. Matthews

AI总结:

针对芯空穴光谱线性响应中芯电子激发的轨道弛豫难题,研究提出纳入芯价分离且仅在芯电离能计算中加三重激发关联的CVS-STEOMEE-CCSD+cT方法,在小分子K边芯激发能计算上精度接近更高级方法。

摘要:

芯电子激发时的轨道弛豫现象是芯空穴光谱线性响应处理中的一大难题。我们并未通过运动方程耦合簇理论(EOMEE-CC)对激发态进行直接动力学关联来解决弛豫问题,而是对替代性的相似变换运动方程耦合簇理论(STEOMEE-CC)进行了扩展,纳入了芯价分离(CVS),且仅在芯电离能计算中纳入三重激发的关联。这种新方法CVS-STEOMEE-CCSD+cT,在一组小分子的K边芯激发能方面,与完全CVS-EOM-CCSDT相比,显著优于CVS-EOMEE-CCSD和未修改的CVS-STEOMEE-CCSD。其在绝对峰位和相对(位移后)峰位上的改进效果,几乎与显式处理轨道弛豫的跃迁势耦合簇(TP-CC)、以及微扰处理三重激发的CVS-EOMEE-CCSD*的效果相当。

英文摘要:

The phenomenon of orbital relaxation upon excitation of core electrons is a major problem in the linear-response treatment of core-hole spectroscopies. Rather than addressing relaxation through direct dynamical correlation of the excited state via equation-of-motion coupled cluster theory (EOMEE-CC), we extend the alternative similarity-transformed equation-of-motion coupled cluster theory (STEOMEE-CC) by including the core-valence separation (CVS) and correlation of triple excitations only within the calculation of core ionization energies. This new method, CVS-STEOMEE-CCSD+cT, significantly improves on CVS-EOMEE-CCSD and unmodified CVS-STEOMEE-CCSD when compared to full CVS-EOM-CCSDT for K-edge core-excitation energies of a set of small molecules. The improvement in both absolute and relative (shifted) peak positions is nearly as good as for transition-potential coupled cluster (TP-CC), which includes an explicit treatment of orbital relaxation, and CVS-EOMEE-CCSD*, which includes a perturbative treatment of triple excitations.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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