Variational reduced-density-matrix method using three-particle N-representability conditions with application to many-electron molecules
Variational reduced-density-matrix method using three-particle N-representability conditions with application to many-electron molecules
复制标题
使用三粒子 N 可表示性条件的变分约化密度矩阵方法及其应用于多电子分子
DOI：
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发表时间：
2006
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通讯作者：
D. Mazziotti
中科院分区：
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作者：
D. Mazziotti
在不考虑多电子波函数的情况下，通过用一组三粒子N-可表示性条件（称为三正性条件）约束2-RDM，变分计算了分子的两电子约化密度矩阵（2-RDM）.这些约束限制了四个不同的三粒子概率分布，这可以定义为任何N粒子系统，是非负的。用一阶半定规划算法[D. A. Mazziotti，Phys. Rev. Lett. 93，213001（2004）]。我们还推导并实现了一个推广的T{sub 2}可表示性条件，这是一个子集的三个积极的条件。能量和2-RDM计算几个分子以及氮分子在平衡和非平衡几何形状。氮的基态能量在0.0015 a. u之内。在所有核间距下的全组态相互作用的值。
Molecular two-electron reduced density matrices (2-RDMs) are computed variationally without the many-electron wave function by constraining the 2-RDM with a set of three-particle N-representability conditions known as three-positivity conditions. These constraints restrict four distinct three-particle probability distributions, which can be defined for any N-particle system, to be nonnegative. The variational calculation of the 2-RDM with full three-positivity conditions is implemented with the first-order semidefinite programming algorithm [D.A. Mazziotti, Phys. Rev. Lett. 93, 213001 (2004)]. We also derive and implement a generalization of the T{sub 2} representability condition, which is a subset of the three-positivity conditions. Energies and 2-RDMs are computed for several molecules as well as the nitrogen molecule at both equilibrium and nonequilibrium geometries. The ground-state energies for nitrogen are within 0.0015 a.u. of the values from full configuration interaction at all internuclear distances.