Relativistic equation-of-motion coupled-cluster method: Application to closed-shell atomic systems
Relativistic equation-of-motion coupled-cluster method: Application to closed-shell atomic systems
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DOI：
10.1103/physreva.89.042510
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发表时间：
2014-01
影响因子：
2.9
通讯作者：
Himadri Pathak;B. Sahoo;B. Das;Nayana Vaval;S. Pal
中科院分区：
文献类型：
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作者：
Himadri Pathak;B. Sahoo;B. Das;Nayana Vaval;S. Pal
我们报告我们成功地实现了相对论运动方程耦合团簇（EOMCC）方法。用这种方法计算了封闭壳层稀有气体原子、类He离子、类Be离子沿着Na${}^{+}$、Al${}^{+}$、K${}^{+}$、Be和Mg的主电离势。四分量狄拉克旋量被用于计算，和一个和两个电子的积分使用狄拉克-库仑哈密顿量进行评估。我们的结果是在良好的协议与现有的测量，这是从国家科学技术研究所的数据库。计算的准确性估计为半个百分点内的He类和Be类离子和1%的较重的系统。我们还使用EOMCC框架中的二阶多体微扰理论和随机相位近似给出了结果。这些结果进行了比较与EOMCC在单，双激发的水平，以评估在我们的计算中考虑的中间方案中的电子相关效应的作用。
We report our successful implementation of the relativistic equation-of-motion coupled-cluster (EOMCC) method. This method is employed to compute the principal ionization potentials (IPs) of closed-shell rare-gas atoms, He-like ions, Be-like ions, along with Na${}^{+}$, Al${}^{+}$, K${}^{+}$, Be, and Mg. Four-component Dirac spinors are used in the calculations, and the one- and two-electron integrals are evaluated using the Dirac-Coulomb Hamiltonian. Our results are in excellent agreement with available measurements, which are taken from the National Institute of Science and Technology database. The accuracies of the calculations are estimated to be within one half of a percent for He-like and Be-like ions and 1% for the heavier systems. We also present results using the second-order many-body perturbation theory and random-phase approximation in the EOMCC framework. These results are compared with those of EOMCC at the level of single and double excitations in order to assess the role of the electron correlation effects in the intermediate schemes considered in our calculations.