Seonglae ChoDensity Functional Theory (DFT)
Electronic structure calculation method: A computational approach that uses electron density as the fundamental variable to approximately solve quantum-mechanical many-electron problems.
A theoretical approach in quantum mechanics used to calculate the electronic structure and energy of matter and molecules. Through DFT, scientists can predict whether specific molecules can exist in nature, as well as their shapes and properties. It represents one of the most widely used quantum mechanical calculation methods in computational science.
Key Concepts:
- Core Principle: Rather than tracking the movement of individual electrons, DFT treats electrons collectively as a single entity.
- Wide Application: DFT can be applied to many-body problems with similar structures, making it useful in various statistical physics applications beyond electronic structure.
- Kohn-Sham Equation: This equation describes the relationship between the shape of the electron density (visualized as a "donut") and energy.
Methodology:
- Self-Consistent Field (SCF) Method: Derived from the Hartree-Fock approach, this iterative technique determines electron density distributions.
- Iterative Process: Starting with an arbitrary electron density model, the system is gradually refined by testing how well it satisfies quantum mechanical constraints and adjusting parameters to better approximate reality.
Energy Considerations:
- Exchange-Correlation Functionals: DFT uses both exchange energy functionals and correlation energy functionals, collectively known as exchange-correlation functionals.
- B3LYP Functional: Currently, the B3LYP functional is widely regarded as reliable across most applications with minimal errors.
