Generalized Hartree–Fock with Nonperturbative Treatment of Strong Magnetic Fields: Application to Molecular Spin Phase Transitions
Generalized Hartree–Fock with Nonperturbative Treatment of Strong Magnetic Fields: Application to Molecular Spin Phase Transitions
复制标题
强磁场非微扰处理的广义 Hartree-Fock：在分子自旋相变中的应用
DOI：
10.1021/acs.jctc.8b01140
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发表时间：
2018
影响因子：
5.5
通讯作者：
Li, Xiaosong
中科院分区：
文献类型：
--
作者：
Sun, Shichao;Williams-Young, David B.;Stetina, Torin F.;Li, Xiaosong
在这项工作中，我们提出了一个从头算变分方法的框架，有效地研究了均匀磁场中分子系统中的电子自旋相变。为了捕捉这一现象，在伦敦轨道的旋量形式中使用了复广义Hartree-Fock(C-GHF)方法。给出了计算伦敦轨道单电子积分和双电子积分的递推算法。引入了C-GHF方法的泡利矩阵表示，将自旋贡献从Fock矩阵的标量部分分离出来。接下来，我们研究了两种不同分子体系在强磁场作用下的自旋相变。在H_2和二铬络合物[(H_3N)_4Cr(OH)_2Cr(NH_3)_4]_4+的自旋相变过程中，观察到了非共线自旋组态，并随着磁场强度的增加而增加。交换耦合和自旋塞曼效应的相互竞争的驱动力已被证明是控制自旋相变及其相变速率的主要因素。此外，还分析了自旋塞曼项、轨道塞曼项和反磁塞曼项对势能面的能量贡献。
In this work, we present a framework of an ab initio variational approach to effectively explore electronic spin phase transitions in molecular systems inside of a homogeneous magnetic field. In order to capture this phenomenon, the complex generalized Hartree–Fock (C‐GHF) method is used in the spinor formalism with London orbitals. Recursive algorithms for computing the one- and two-electron integrals of London orbitals are also provided. A Pauli matrix representation of the C‐GHF method is introduced to separate spin contributions from the scalar part of the Fock matrix. Next, spin phase transitions in two different molecular systems are investigated in the presence of a strong magnetic field. Noncollinear spin configurations are observed during the spin phase transitions in H2and a dichromium complex, [(H3N)4Cr(OH)2Cr(NH3)4]4+, with an increase in magnetic field strength. The competing driving forces of exchange coupling and the spin Zeeman effect have been shown to govern the spin phase transition and its transition rate. Additionally, the energetic contributions of the spin Zeeman, orbital Zeeman, and diamagnetic terms to the potential energy surface are also analyzed.