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

Exchange and correlation energy in density functional theory: Comparison of accurate density functional theory quantities with traditional Hartree–Fock based ones and generalized gradient approximations for the molecules Li2, N2, F2

The density functional definition of exchange and correlation differs from the traditional one. In order to calculate the density functional theory ~DFT!, quantities accurately, molecular Kohn–Sham ~KS! solutions have been obtained from ab initio wave functions for the homonuclear diatomic molecules Li2, N2, F2. These afford the construction of the KS determinant Cs and the calculation of its t...

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

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...

Multiresolution Quantum Chemistry in Multiwavelet Bases

A multiresolution solver is presented for all-electron Hartree-Fock and Kohn-Sham equations for general polyatomic molecules. The distinguishing features of our numerical solver are that the basis error is eliminated within a user-specified precision, the computational cost of applying operators scales linearly with the number of parameters in a correct physical sense, and the equations are sol...

Orbitals in Quantum Chemistry

Orbitals, on the one hand, are often considered as auxiliary quantities without physical meaning for various reasons. Slater determinants, e.g., Hartree-Fock or Kohn-Sham determinants, are invariant with respect to unitary transformations of the occupied orbitals. Within densityfunctional theory (DFT) orbitals frequently are considered as quantities that merely generate the electron density but...