Gidofalvi Gergely, Mazziotti David A
Department of Chemistry and the James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA.
J Phys Chem A. 2006 Apr 27;110(16):5481-6. doi: 10.1021/jp056392j.
The variational optimization of the energy with respect to the two-electron reduced-density matrix (2-RDM), constrained by N-representability conditions, can determine the shape of molecular potential energy surfaces with useful accuracy. In this paper, we apply the 2-RDM method with a first-order optimization algorithm [Mazziotti, D. A. Phys. Rev. Lett. 2004, 93, 213001] to investigating the potential energy surfaces of carbon monoxide in the presence and absence of an electric field. Two beneficial characteristics of the 2-RDM method for computing potential energy surfaces include the following: (i) its ability to capture multireference effects without specifying any reference wave function or density matrix and (ii) its guarantee of a global energy minimum in the variational optimization. The 2-RDM method produces electronic ground-state energies with similar accuracy at equilibrium and nonequilibrium geometries in both the presence and the absence of the electric field. Computed dipole moments are similar in accuracy to the values from the computationally expensive configuration interaction with single, double, triple, and quadruple excitations. These surfaces have important applications in quantum molecular control theory.
在N可表示性条件的约束下，关于双电子约化密度矩阵（2-RDM）的能量变分优化能够以有用的精度确定分子势能面的形状。在本文中，我们将具有一阶优化算法的2-RDM方法[马佐蒂，D. A.《物理评论快报》2004年，93卷，213001]应用于研究存在和不存在电场时一氧化碳的势能面。2-RDM方法用于计算势能面的两个有益特性如下：（i）它能够在不指定任何参考波函数或密度矩阵的情况下捕捉多参考效应；（ii）它在变分优化中保证全局能量最小。2-RDM方法在存在和不存在电场的情况下，在平衡和非平衡几何构型下产生的电子基态能量具有相似的精度。计算得到的偶极矩在精度上与来自计算成本高昂的单、双、三、四重激发组态相互作用的值相似。这些表面在量子分子控制理论中有重要应用。
