Title: An Efficient Algorithm for Constrained CASSCF(1,2) and CASSCF(3,2) Simulations as Relevant to Electron and Hole Transfer Problems Show Chinese title

Title: 一种用于约束CASSCF(1,2)和CASSCF(3,2)模拟的高效算法，适用于电子和空穴转移问题

Abstract: We propose an efficient algorithm for the recently published electron/hole-transfer Dynamical-weighted State-averaged Constrained CASSCF (eDSC/hDSC) method studying charge transfer states and D$_1$-D$_0$ crossings for systems with odd numbers of electrons. By separating the constrained minimization problem into an unconstrained self-consistent-field (SCF) problem and a constrained non-self-consistent-field (nSCF) problem, and accelerating the direct inversion in the iterative subspace (DIIS) technique to solve the SCF problem, the overall computational cost is reduced by a factor of 8 to 20 compared with directly using sequential quadratic programming (SQP). This approach should be applicable for other constrained minimization problems and, in the immediate future, once gradients are available, the present eDSC/hDSC algorithm should allow for speedy non-adiabatic dynamics simulations. Show Chinese abstract

Abstract: 我们提出了一种高效的算法，用于最近发表的电子/空穴转移动力学加权状态平均约束CASSCF (eDSC/hDSC) 方法，研究具有奇数个电子的系统的电荷转移态和D$_1$-D$_0$交叉。通过将约束最小化问题分为无约束自洽场 (SCF) 问题和约束非自洽场 (nSCF) 问题，并加速直接迭代子空间逆 (DIIS) 技术来求解SCF问题，与直接使用顺序二次规划 (SQP) 相比，总体计算成本降低了8到20倍。这种方法应适用于其他约束最小化问题，并且在不久的将来，一旦获得梯度，当前的eDSC/hDSC算法应能实现快速非绝热动力学模拟。