Kohn-Sham Density in a Slater Orbital Basis Set.

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Electronic Structure Theory

Background:

• Accurate determination of molecular orbitals is crucial for understanding chemical properties.
• Finite basis sets are commonly used in electronic structure calculations, introducing approximations.
• Kohn-Sham (KS) density functional theory provides a framework for approximating electronic structure.

Purpose of the Study:

• To develop a systematic method for determining approximate Kohn-Sham molecular orbitals using finite, atom-centered Slater basis sets.
• To introduce a weight factor to balance kinetic energy and density difference minimization components.
• To analyze the electronic structure of diatomic molecules, such as LiH, with fractional electron counts.

Main Methods:

• Minimization of kinetic energy and the sum-squared difference between KS and full configuration interaction densities.
• Employment of finite, atom-centered Slater basis sets.
• Application of a weight factor to balance competing minimization objectives.
• Analysis of the LiH diatomic molecule with fractional electron counts.

Main Results:

• A systematic method for approximating KS orbitals was established, showing robustness against scaling factor choices.
• The method successfully captured the KS orbital structure for LiH with fractional electron counts.
• Significant electron density reorganization upon bond stretching in LiH was observed and analyzed.

Conclusions:

• The developed approach provides a reliable way to obtain approximate KS orbitals from finite basis sets.
• The study highlights the influence of electron correlation and locality on KS solutions.
• This method offers insights into the electronic behavior of molecules under varying electron counts and geometries.