An Efficient Algorithm for Constrained CASSCF(1,2) and CASSCF(3,2) Simulations as Relevant to Electron and Hole Transfer Problems
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-D 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.
Cite
@article{arxiv.2409.14631,
title = {An Efficient Algorithm for Constrained CASSCF(1,2) and CASSCF(3,2) Simulations as Relevant to Electron and Hole Transfer Problems},
author = {Tian Qiu and Joseph E. Subotnik},
journal= {arXiv preprint arXiv:2409.14631},
year = {2024}
}