论文标题
过渡势耦合群集
Transition-Potential Coupled Cluster
论文作者
论文摘要
在包括X射线吸收和X射线光电离在内的计算核心孔光谱中轨道松弛的问题长期以来一直困扰着线性响应方法，包括带有单打和双打（EOM-CCSD）的运动方程耦合群集。我们没有通过使用“过渡势”参考轨道对轨道放松的明确处理来解决此问题，而是导致过渡潜力耦合簇（TP-CC）的方法家族。尤其是该家族的一个成员TP-CCSD（1/2）基本上消除了轨道放松误差，并达到了核心孔光谱的准确性水平，通常与Valence区域的EOM-CCSD相同。这些结果表明，具有第一行原子分子的非常精确的X射线吸收光谱可以以与EOM-CCSD相同的成本计算。
The problem of orbital relaxation in computational core-hole spectroscopies, including x-ray absorption and x-ray photoionization, has long plagued linear response approaches, including equation-of-motion coupled cluster with singles and doubles (EOM-CCSD). Instead of addressing this problem by including additional electron correlation, we propose an explicit treatment of orbital relaxation via the use of "transition potential" reference orbitals, leading to a transition-potential coupled cluster (TP-CC) family of methods. One member of this family in particular, TP-CCSD(1/2), is found to essentially eliminate the orbital relaxation error and achieve the same level of accuracy for core-hole spectra as is typically expected of EOM-CCSD in the valence region. These results show that very accurate x-ray absorption spectra for molecules with first-row atoms can be computed at a cost essentially the same as that for EOM-CCSD.
