Density Functional Theory under the Bubbles and Cube Numerical Framework.

Area of Science:

• Computational chemistry
• Quantum chemistry
• Materials science

Background:

• Density functional theory (DFT) is a powerful quantum mechanical modeling method.
• Accurate electronic structure calculations are crucial for understanding molecular properties.
• Existing methods face challenges with computational efficiency and accuracy for certain systems.

Purpose of the Study:

• To implement Kohn-Sham density functional theory (KS-DFT) within a real-space framework.
• To develop a computational method using "bubbles" and "cubes" for efficient electronic structure calculations.
• To assess the accuracy of the implemented KS-DFT method for light atoms and small molecules.

Main Methods:

• Utilized a real-space molecular electronic structure framework.
• Expanded functions with steep nuclear cusps using atom-centered 1D numerical grids and spherical harmonics ("bubbles").
• Represented the remaining smooth part of the molecular function on a 3D equidistant grid ("cube").

Main Results:

• Successfully implemented 3D numerical KS-DFT calculations.
• Performed calculations on light atoms and small molecules.
• Obtained accurate energies, validated by comparison with established reference data.

Conclusions:

• The "bubbles and cube" real-space KS-DFT framework is a viable approach for electronic structure calculations.
• The method demonstrates good accuracy for small systems.
• This framework offers a promising alternative for computational quantum chemistry.