Open-shell reduced density matrix functional theory.
Open-shell reduced density matrix functional theory.
复制标题
开壳约化密度矩阵泛函理论。
DOI：
10.1063/1.3624609
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
K. Pernal
中科院分区：
文献类型：
--
作者：
Daniel R. Rohr;K. Pernal
通过研究精确泛函的定义域，建立了开壳约化密度矩阵泛函理论。对于作为基态的自旋态，一个特别简单的集合被发现是磁区。它不能推广到其他自旋态。给出了精确密度矩阵泛函满足的若干条件，并对近似泛函进行了检验。精确泛函不受分数自旋误差的影响，分数自旋误差是解离分子静态关联误差的来源。我们证明了一个简单的近似(称为Buijse-Baerends泛函、Müler或平方根泛函)具有非正的分数自旋误差。在H原子的情况下，误差为零。给出了几个原子的近似密度泛函和密度矩阵泛函的数值结果，以及最近发展起来的距离分离的两者的组合。
Open-shell reduced density matrix functional theory is established by investigating the domain of the exact functional. For spin states that are the ground state, a particularly simple set is found to be the domain. It cannot be generalized to other spin states. A number of conditions satisfied by the exact density matrix functional is formulated and tested for approximate functionals. The exact functional does not suffer from fractional spin error, which is the source of the static correlation error in dissociated molecules. We prove that a simple approximation (called the Buijse-Baerends functional, Müller or square root functional) has a non-positive fractional spin error. In the case of the H atom the error is zero. Numerical results for a few atoms are given for approximate density and density matrix functionals as well as a recently developed range-separated combination of both.