Orthogonally Constrained Orbital Optimization: assessing changes of optimal orbitals for orthogonal multi-reference states
arXiv:2211.08329 · doi:10.1021/acs.jctc.2c01144
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.
References in corpus (9)
- A Mountaineering Strategy to Excited States: Highly-Accurate Reference Energies and Benchmarks
- A deterministic alternative to the full configuration interaction quantum Monte Carlo method
- The density matrix renormalization group for ab initio quantum chemistry
- Delta Self-Consistent Field as a method to obtain potential energy surfaces of excited molecules on surfaces
- Excited state orbital optimization via minimizing the square of the gradient: General approach and application to singly and doubly excited states via density functional theory
- An Efficient Matrix Product Operator Representation of the Quantum-Chemical Hamiltonian
- Variational density functional calculations of excited states via direct optimization
- Orbital Optimization in Selected Configuration Interaction Methods
- Tailoring CIPSI expansions for QMC calculations of electronic excitations: the case study of thiophene