Model Hamiltonians
******************

      **See also:**
      spin-orbit coupling
      Examples: special XC functionals, relativistic effects, solvents, other environments

* Electronic Configuration

  * Charge and Spin

  * Orbital occupations: electronic configuration, excited states

  * Frozen core approximation

  * Spin-polarized start-up potential

  * Unrestricted fragments

  * Simulated unrestricted fragments with key FRAGOCCUPATIONS

  * Remove Fragment Orbitals

  * CDFT: Constrained Density Functional Theory

  * FOCDFT: Fragment Orbital Constrained DFT

* Density Functionals (XC)

  * LDA

  * GGA

  * MetaGGA

  * Hartree-Fock

  * Hybrid

  * Meta-Hybrid

  * Range-separated hybrids

  * Notes on Hartree-Fock and (meta-)hybrid functionals

  * MP2, Double Hybrids, RPA

  * Model Potentials

  * XCFun

  * LibXC

  * Dispersion corrections

  * Post-SCF energy functionals

* Relativistic effects

  * Pauli

  * ZORA

  * X2C and RA-X2C

  * Spin-Orbit coupling

* Solvents and other environments

  * COSMO: Conductor-like Screening Model

  * SM12: Solvation Model 12

  * Quild

  * Hybrid Engine (QM/MM, QM/QM')

  * DIM/QM: Discrete Interaction Model/Quantum Mechanics

  * QM/FQ: Quantum Mechanics/Fluctuating Charges (and Fluctuating
    Dipoles)

  * QM/ωFQ: Quantum Mechanics/Frequency-Dependent Fluctuating Charges
    (and Fluctuating Dipoles)

  * FDE: Frozen Density Embedding

  * 3D-RISM: 3D Reference Interaction Site Model

* Electric Field: Homogeneous, Point Charges, Polarizability
