Orthogonally Constrained Orbital Optimization: assessing changes of optimal orbitals for orthogonal multi-reference states
Quantum Physics
2023-02-16 v1
Abstract
The choice of molecular orbitals is decisive in configuration interaction calculations. In this letter, a democratic description of the ground and excited states follows an orthogonally constrained orbitals optimization to produce state-specific orbitals. The approach faithfully recovers the excitation energy of afour-electron Hubbard trimer, whereas state-average calculations can miss the value by a factor 2.5. The method emphasises the need for orbitals optimizationto reduce expansions and to reach spectroscopic accuracy.
Cite
@article{arxiv.2211.08329,
title = {Orthogonally Constrained Orbital Optimization: assessing changes of optimal orbitals for orthogonal multi-reference states},
author = {Saad Yalouz and Vincent Robert},
journal= {arXiv preprint arXiv:2211.08329},
year = {2023}
}