A full implementation of the response iteration scheme for density functional calculations.

Area of Science:

• Computational physics and chemistry
• Quantum mechanics
• Materials science

Background:

• Solving the Kohn-Sham equations is crucial for understanding electronic structure.
• Traditional methods often require calculating unoccupied states, increasing computational cost.
• Efficient algorithms are needed for complex many-body systems.

Purpose of the Study:

• To implement and present a novel response algorithm for solving Kohn-Sham-like equations.
• To develop a method that directly computes the electron density.
• To enable calculations for arbitrary geometries without explicit unoccupied states.

Main Methods:

• Direct solution for (spin) density.
• Implementation for arbitrary geometries.
• Application to molecules (C6H6, C60) and metal clusters (Mg30, Na40).

Main Results:

• The algorithm successfully solves Kohn-Sham equations directly for electron density.
• Calculations were performed for various molecular and metallic systems.
• Significantly faster convergence was achieved compared to previous update algorithms, even from poor initial guesses.

Conclusions:

• The implemented response algorithm offers a more efficient approach to electronic structure calculations.
• This method bypasses the need for unoccupied states, reducing computational burden.
• It provides a faster and robust alternative for studying inhomogeneous many-body systems.