Centre for Theoretical Chemistry and Physics, New Zealand Institute for Advanced Study, Massey University, Auckland Campus, Private Bag 102904, North Shore City, 0745 Auckland, New Zealand.
J Chem Phys. 2010 Mar 21;132(11):114301. doi: 10.1063/1.3354976.
The potential energy curve of the electronic ground state of the mercury dimer based on CCSD(T) calculations at the complete basis set (CBS) limit, including corrections for the full triples DeltaT and explicit spin-orbit (SO) interactions at the CCSD(T) level of theory, is presented. In the far long-range part, the potential energy curve is complemented by symmetry-adapted perturbation theory calculations. Potential curves of an analytically simple, extended Lennard-Jones form are obtained from very accurate fits to the CBS/CCSD(T)+SO and CBS/CCSD(T)+SO+DeltaT data. The Hg(2) potential curves yield dissociation energies of D(e)=424/392 cm(-1) and equilibrium distances of r(e)=3.650/3.679 A at the CBS/CCSD(T)+SO and CBS/CCSD(T)+SO+DeltaT levels of theory, respectively. By including perturbative quadruple corrections in our coupled-cluster calculations and corrections from correlating the 4f-core, we arrive at a final dissociation energy of D(e)=405 cm(-1), in excellent agreement with the experimentally estimated value of 407 cm(-1) by Greif and Hensel. In addition, the rotational and vibrational spectroscopic constants as well as the second virial coefficient B(T) in dependence of the temperature T are calculated and validated against available experimental and theoretical data.
基于完全基组（CBS）限制下 CCSD(T) 计算的汞二聚体电子基态的势能曲线，包括在 CCSD(T) 理论水平上对全三重态 DeltaT 和显式自旋-轨道（SO）相互作用的修正，被呈现出来。在远长程部分，通过对称性自适应微扰理论计算来补充势能曲线。通过对 CBS/CCSD(T)+SO 和 CBS/CCSD(T)+SO+DeltaT 数据进行非常精确的拟合，得到了具有简单解析形式的扩展 Lennard-Jones 形式的势能曲线。Hg(2) 势能曲线在 CBS/CCSD(T)+SO 和 CBS/CCSD(T)+SO+DeltaT 理论水平下给出了离解能 D(e)=424/392 cm(-1)和平衡距离 r(e)=3.650/3.679 A。通过在我们的耦合簇计算中包含微扰四重修正和关联 4f 核的修正，我们得到了最终的离解能 D(e)=405 cm(-1)，与 Greif 和 Hensel 通过实验估计的 407 cm(-1)值非常吻合。此外，还计算并验证了依赖于温度 T 的转动和振动光谱常数以及第二维里系数 B(T)，与可用的实验和理论数据相吻合。
