Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, United States.
Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States.
J Phys Chem A. 2020 Jun 4;124(22):4413-4426. doi: 10.1021/acs.jpca.0c00901. Epub 2020 May 26.
Benchmark scalar-relativistic delta-coupled-cluster calculations of hetero-site double core ionization energies of small molecules containing second-row elements are reported. The present study has focused on the high-spin triplet components of two-site double core-ionized states, which are single reference in character and consistent with the use of standard coupled-cluster methods. Contributions to computed double core ionization energies from electron-correlation and basis-set effects as well as corrections to the core-valence separation approximation have been analyzed. On the basis of systematic convergence of computational results with respect to these effects, delta-coupled-cluster calculations have been shown to be capable of providing accurate double core ionization energies with remaining errors estimated to be below 0.3 eV, and thus they are recommended for use to facilitate experimental studies of two-site double core-ionized states that are involved in X-ray pump/X-ray probe studies of electronic and molecular dynamics following inner shell ionization or excitation.
报道了含第二周期元素小分子异核双芯电离能的基准标量相对论关联簇计算。本研究集中于双芯离化态的二位点高自旋三重态分量，其在性质上为单参考态，与标准关联簇方法的使用一致。分析了电子相关和基组效应对计算双芯电离能的贡献以及对芯-价分离近似的修正。基于这些效应的计算结果的系统收敛性，表明关联簇计算能够提供准确的双芯电离能，剩余误差估计在 0.3 eV 以下，因此建议将其用于促进涉及内壳电离或激发后电子和分子动力学的 X 射线泵/X 射线探针研究的双芯离化态的实验研究。
