Controlling spin contamination using constrained density functional theory.
Controlling spin contamination using constrained density functional theory.
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使用约束密度泛函理论控制自旋污染。
DOI：
10.1063/1.2978168
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
J. Tully
中科院分区：
文献类型：
--
作者：
J. R. Schmidt;N. Shenvi;J. Tully
我们扩展了约束密度泛函理论（DFT）方法，以显式控制自旋污染的大小。与受限或受限开壳方法不同，本方法允许更精细的粒度，不仅约束自旋污染的大小，而且允许将约束应用于大得多的系统的子系统的可能性。这允许在物理上有意义的地方描述自旋极化，同时能够减少许多DFT泛函中存在的杂散过极化。我们利用这个约束在两个特定的模型应用：各向同性和各向异性的超精细耦合的过渡金属配合物，[Mn（CN）（5）NO]（2-）的计算，和计算的非绝热解离曲线的OF自由基。在这两种情况下，自旋污染约束是必不可少的，获得物理意义上的，定性正确的结果。
We have extended the constrained density functional theory (DFT) approach to explicitly control the magnitude of spin contamination. Unlike a restricted or restricted open-shell approach, the present method allows finer granularity, not only constraining the magnitude of the spin contamination but also allowing for the possibility of applying the constraint to a subsystem of a much larger system. This allows for the description of spin polarization where physically meaningful, while simultaneously enabling the reduction of spurious overpolarization that is present in many DFT functionals. We utilize this constraint in two particular model applications: The calculation of isotropic and anisotropic hyperfine couplings of a transition metal complex, [Mn(CN)(5)NO](2-), and the calculation of the diabatic dissociation curves of OF radical. In both cases, the spin contamination constraint is essential for obtaining physically meaningful, qualitatively correct, results.