What are the key concepts and abbreviations related to DFT and HF theory?

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Key concepts related to DFT and HF theory include SCF, which is an iterative method for solving the Schrödinger equation to determine electronic structures, and the Slater determinant, which represents multi-part wave functions for fermions ensuring antisymmetry. Exchange energy refers to the energy change when electrons with the same spin swap positions, while correlation energy is associated with multiple electrons occupying the same orbit. Self-interaction error is a Hartree-Fock limitation that leads to energy overestimation by neglecting electron-electron repulsion, and Post Hartree-Fock methods enhance accuracy by adding terms beyond the Hartree-Fock approximation. The PW91 functional is a DFT approach that improves electronic structure calculations, and the Born-Oppenheimer approximation simplifies quantum mechanical calculations by decoupling electron and nuclear motions.
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I hope you guys can help me understand these concepts better, did'nt find so much on google. This is from an old exam, I am preparing for my exam and I feel that I need to have an simple understatement of these.
Thanks a lot!

1. Homework Statement

Explain the following concepts and abbreviations in a concise manner. Also make relevant comments on how the concepts relate to DFT and HF
”SCF”

”Slater determinant”

”Exchange energy”

”Correlation energy”

”Self-interaction error”

“Post Hartree-Fock methods”

“PW91”

“BO approximation”

Homework Equations

The Attempt at a Solution



SCF - SCF is an iterative method that selects an approximate Hamiltonian, which solves the Schrödinger equation to get a more accurate set of orbits, and then resolves the Schrödinger equation with theses until the results coincide.
SCF is used to study the electronic structure of atoms with more than one electron. The HF approximation is also known as an SCF method.

Slater determinant - is what is called a determinant of spin orbital and is a way of writing wave functions to easily generate wave functions that are antisymmetric.

A Slater determinant is a representation of a multi-part wave function for a system of fermions that meet the requirements for antisymmetry. In other words, the wave function changes the sign of the exchange of two particle coordinates.

Exchange energy - It's the energy released when two or more electrons with the same spin change their positions in degenerate orbits. This term is not a feature of a given wave function or Hamiltonian. But within the Hartree-Fock and Kohn-Sham theories, it has clear meanings, namely, the energy contribution to the total energy due to the exchange of HF.
 
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Correlation energy - It is the energy released or created when two or more electrons occupy the same orbit. This energy is a feature of a given wave function or Hamiltonian and is not related to the exchange of electrons.Self-interaction error - It is an error in the Hartree-Fock method, where the electron's own electrostatic potential is underestimated. This leads to an overestimation of the energy of the system, since it ignores the Coulomb repulsion between an electron and itself.Post Hartree-Fock methods - Post Hartree-Fock methods are methods that improve the accuracy of the Hartree-Fock approximation by introducing additional terms into the Hamiltonian beyond those used in the Hartree-Fock approximation. These methods include configuration interaction (CI) and coupled cluster theory (CC).PW91 - Also known as the Perdew-Wang 91 functional, is a type of density functional theory (DFT) for calculating the electronic structure of molecules. The PW91 functional was developed by John P. Perdew and Yong Wang in 1991 as an improvement over the local density approximation (LDA).BO Approximation - The Born–Oppenheimer approximation (BOA) is a method to reduce the complexity of quantum mechanical calculations of molecular systems. It is based on the idea that the motion of electrons around the nucleus can be separated from the motion of the nucleus itself, and that the motion of the electrons can be treated separately. The BOA is widely used in quantum chemistry, and is the basis of the Hartree–Fock method.
 

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