The cyclic cluster model at Hartree-Fock level.

Area of Science:

• Computational Chemistry
• Solid-State Physics
• Quantum Chemistry

Background:

• Periodic models are standard for solid-state calculations.
• Existing methods often require significant computational resources.
• A need exists for efficient and accurate quantum chemical approaches for condensed matter.

Purpose of the Study:

• To implement the cyclic cluster model (CCM) formalism at the Hartree-Fock (HF) level.
• To adapt molecular quantum chemistry methods for solid-state problems.
• To validate the CCM approach against conventional supercell models.

Main Methods:

• Implementation of the cyclic cluster model (CCM) at the Hartree-Fock (HF) level.
• Utilizing a Γ-point approach with real-space integration within a finite cluster.
• Careful treatment of three- and four-center integrals at the Wigner-Seitz supercell boundary.

Main Results:

• Successful implementation of the CCM formalism at the HF level.
• Demonstrated ability to reproduce electronic structure and energetics of conventional supercell models.
• Validation using selected model systems.

Conclusions:

• The CCM provides a viable and accurate alternative for solid-state electronic structure calculations.
• The approach allows for the application of advanced post-HF methods to condensed matter.
• This work bridges molecular and solid-state quantum chemistry.