Correlation potentials and functionals in Hartree-Fock-Kohn-Sham theory

Correlation potentials and functionals in Hartree-Fock-Kohn-Sham theory

Exact Kohn-Sham versus Hartree-Fock in momentum space: Examples of two-fermion systems.

The question of how density functional theory (DFT) compares with Hartree-Fock (HF) for the computation of momentum-space properties is addressed in relation to systems for which (near) exact Kohn-Sham (KS) and HF one-electron matrices are known. This makes it possible to objectively compare HF and exact KS and hence to assess the potential of DFT for momentum-space studies. The systems conside...

Hartree-Fock and Kohn-Sham time-dependent response theory in a second-quantization atomic-orbital formalism suitable for linear scaling.

We present a second-quantization based atomic-orbital method for the computation of time-dependent response functions within Hartree-Fock and Kohn-Sham density-functional theories. The method is suited for linear scaling. Illustrative results are presented for excitation energies, one- and two-photon transition moments, polarizabilities, and hyperpolarizabilities for hexagonal BN sheets with up...

Comparison of Hartree-Fock and Kohn-Sham determinants as wave functions

Kohn–Sham (KS) and Hartree–Fock (HF) determinants were used as the true many-body wave functions for calculations of molecular energies, vibrational frequencies, and excited electronic states. The results justified common practice, encountered in the sum over states theories, in which these two determinants are used as the first-order approximation of the wave function. However, a distinct beha...

A stepwise atomic, valence-molecular, and full-molecular optimisation of the Hartree-Fock/Kohn-Sham energy.

A hierarchical optimisation strategy has been introduced for minimising the Hartree-Fock/Kohn-Sham energy, consisting of three levels (3L): an atom-in-a-molecule optimisation, a valence-basis molecular optimisation, and a full-basis molecular optimisation. The density matrix formed at one level is used as a starting density matrix at the next level with no loss of information. To ensure a fast ...