Multireference calculations on the ground and lowest excited states and dissociation energy of LuF
Multireference calculations on the ground and lowest excited states and dissociation energy of LuF
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DOI：
10.1063/5.0052312
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发表时间：
2021-06-28
影响因子：
4.4
通讯作者：
Wilson, Angela K.
中科院分区：
文献类型：
--
作者：
Almeida, Nuno M. S.;Melin, Timothe R. L.;Wilson, Angela K.
对LuF的132个态进行了高水平多参考计算，包括4个解离通道Lu（D-2）+ F（P-2），Lu（P-2）+ F（P-2）和2个Lu（F-4）+ F（P-2）。活性空间中包括了镥的6s、5d和6p轨道，沿着着氟的2 p和3 p轨道，使得静态和动态关联的描述更加准确。Lu（F-4）+ F（P-2）通道具有与Lu（P-2）+ F（P-2）和Lu（D-2）+ F（P-2）通道的系统间自旋交叉，这在本文中讨论。为了获得光谱常数、键长和激发态，在四重zeta基组水平下使用多参考构型相互作用（MRCI），还关联4f电子和相应的轨道。核自旋轨道（C-MRCI）计算表明，1（3）Pi（0-）是第一个激发态，紧随其后的是1（3）Pi（0+）。此外，在不同的理论水平，与一系列的基组的LuF的解离能进行了测定。核心相关性和电子的相对论处理之间的平衡是获得解离能的准确描述的基础。最好的预测得到的耦合簇单，双，微扰三重激发/道格拉斯-克罗尔-赫斯三阶哈密顿方法在一个完整的基组水平与零点能量校正的组合，产生的解离值为170.4千卡摩尔（-1）。使用密度泛函理论计算解离能，使用一系列的泛函和基组; M06-L和B3 LYP提供了最接近最佳从头计算的预测。由AIP Publishing独家授权出版。
High level multireference calculations were performed for LuF for a total of 132 states, including four dissociation channels Lu(D-2) + F(P-2), Lu(P-2) + F(P-2), and two Lu(F-4) + F(P-2). The 6s, 5d, and 6p orbitals of lutetium, along with the valence 2p and 3p orbitals of fluorine, were included in the active space, allowing for the accurate description of static and dynamic correlation. The Lu(F-4) + F(P-2) channel has intersystem spin crossings with the Lu(P-2) + F(P-2) and Lu(D-2) + F(P-2) channels, which are discussed herein. To obtain spectroscopic constants, bond lengths, and excited states, multi-reference configuration interaction (MRCI) was used at a quadruple-zeta basis set level, correlating also the 4f electrons and corresponding orbitals. Core spin-orbit (C-MRCI) calculations were performed, revealing that 1(3)Pi(0-) is the first excited state closely followed by 1(3)Pi(0+). In addition, the dissociation energy of LuF was determined at different levels of theory, with a range of basis sets. A balance between core correlation and a relativistic treatment of electrons is fundamental to obtain an accurate description of the dissociation energy. The best prediction was obtained with a combination of coupled-cluster single, double, and perturbative triple excitations /Douglas-Kroll-Hess third order Hamiltonian methods at a complete basis set level with a zero-point energy correction, which yields a dissociation value of 170.4 kcal mol(-1). Dissociation energies using density functional theory were calculated using a range of functionals and basis sets; M06-L and B3LYP provided the closest predictions to the best ab initio calculations. Published under an exclusive license by AIP Publishing.