论文标题
通过直接优化对激发态的变分密度功能计算
Variational density functional calculations of excited states via direct optimization
论文作者
论文摘要
普遍使用的自洽场（SCF）程序的局限性阻碍了变异密度功能理论对激发电子状态的发展。提出了一种基于直接优化方法以及最大重叠方法的方法，并且与先前提出的SCF策略相比，性能。激发态溶液对应于能量的马鞍点，这是电子自由度的函数。此处介绍的方法利用了借助于最大重叠方法确定的预处理，以指导目标n阶鞍点上的收敛性。发现该方法比以前提出的SCF方法更强大，并且收敛的速度更快。对称级别的一种方法的有限记忆公式可更新逆Hessian，可以提供最佳性能。计算一氧化碳分子的圆锥形交叉点，而无需诉诸分数职业数量。提出了对氢原子激发态的计算以及使用自相互作用校正功能的二氢分子的双激发态的计算。对于这些系统，发现自我交互校正可提高激发态密度功能计算的准确性。
The development of variational density functional theory approaches to excited electronic states is impeded by limitations of the commonly used self-consistent field (SCF) procedure. A method based on a direct optimization approach as well as the maximum overlap method is presented and the performance compared with previously proposed SCF strategies. Excited-state solutions correspond to saddle points of the energy as a function of the electronic degrees of freedom. The approach presented here makes use of a preconditioner determined with the help of the maximum overlap method to guide the convergence on a target nth-order saddle point. The method is found to be more robust and to converge faster than previously proposed SCF approaches for a set of 89 excited states of molecules. A limited-memory formulation of the symmetric rank-one method for updating the inverse Hessian is found to give the best performance. A conical intersection for the carbon monoxide molecule is calculated without resorting to fractional occupation numbers. Calculations on excited states of the hydrogen atom and a doubly excited state of the dihydrogen molecule using a self-interaction corrected functional are presented. For these systems, the self-interaction correction is found to improve the accuracy of density functional calculations of excited states.
