Institute for Theoretical Chemistry, University of Cologne, Greinstr. 4, 50939 Cologne, Germany.
J Chem Phys. 2012 Jun 7;136(21):214105. doi: 10.1063/1.4723805.
Energy-consistent two-component semi-local pseudopotentials for the superheavy elements with atomic numbers 111-118 have been adjusted to fully relativistic multi-configuration Dirac-Hartree-Fock calculations based on the Dirac-Coulomb Hamiltonian, including perturbative corrections for the frequency-dependent Breit interaction in the Coulomb gauge and lowest-order quantum electrodynamic effects. The pseudopotential core includes 92 electrons corresponding to the configuration [Xe]4f(14)5d(10)5f(14). The parameters for the elements 111-118 were fitted by two-component multi-configuration Hartree-Fock calculations in the intermediate coupling scheme to the total energies of 267 up to 797 J levels arising from 31 up to 62 nonrelativistic configurations, including also anionic and highly ionized states, with mean absolute errors clearly below 0.02 eV for averages corresponding to nonrelativistic configurations. Primitive basis sets for one- and two-component pseudopotential calculations have been optimized for the ground and excited states and exhibit finite basis set errors with respect to the finite-difference Hartree-Fock limit below 0.01 and 0.02 eV, respectively. General contraction schemes have been applied to obtain valence basis sets of polarized valence double- to quadruple-zeta quality. Results of atomic test calculations in the intermediate coupling scheme at the Fock-space coupled-cluster level are in good agreement with those of corresponding fully relativistic all-electron calculations based on the Dirac-Coulomb-Breit Hamiltonian. The results demonstrate besides the well-known need of a relativistic treatment at the Dirac-Coulomb level also the necessity to include higher-order corrections for the superheavy elements.
已针对原子序数为 111-118 的超重元素，调整了能量一致的双分量半局域赝势，使其与基于 Dirac-Coulomb 哈密顿量的全相对论多组态 Dirac-Hartree-Fock 计算相匹配，其中包括在库仑规范下对频变 Breit 相互作用以及最低阶量子电动力学效应的微扰修正。赝势核心包含 92 个电子，对应于 [Xe]4f(14)5d(10)5f(14)的组态。通过在中间耦合方案下进行双分量多组态 Hartree-Fock 计算，对 111-118 元素的参数进行了拟合，拟合对象是 31 到 62 个非相对论组态中总共 267 到 797 J 的能级的总能量，其中还包括阴离子和高度离化态。对于平均对应于非相对论组态的能量，平均绝对误差明显低于 0.02 eV。针对基态和激发态，对单分量和双分量赝势计算的基组进行了优化，其相对于有限差分 Hartree-Fock 极限的有限基组误差分别小于 0.01 和 0.02 eV。已应用广义收缩方案，以获得极化价双至四zeta 质量的价基组。在 Fock 空间耦合簇水平的中间耦合方案中进行的原子测试计算的结果与基于 Dirac-Coulomb-Breit 哈密顿量的相应全相对论全电子计算的结果非常吻合。结果表明，除了在 Dirac-Coulomb 水平上需要进行相对论处理之外，对于超重元素，还需要包括更高阶修正。
