Periodic Bootstrap Embedding.

Area of Science:

• Computational chemistry
• Materials science
• Solid-state physics

Background:

• Bootstrap embedding (BE) is a novel electronic structure method.
• BE has demonstrated success in treating electron correlation in molecules.

Purpose of the Study:

• Extend Bootstrap embedding (BE) to surfaces and solids.
• Apply BE to systems using periodic boundary conditions and k-point sampling.
• Enable the use of traditional nonperiodic electronic structure codes for fragments of periodic systems.

Main Methods:

• Representing wave functions in periodic boundary conditions using reciprocal space sums (k-point sampling).
• Developing fragment Hamiltonians independent of reciprocal space sums.
• Utilizing coupled cluster singles and doubles (CCSD) to solve fragment Hamiltonians.
• Applying minimal basis set CCSD-in-HF calculations to 1D conducting polymers.

Main Results:

• Periodic BE-CCSD recovers approximately 99.9% of the electron correlation energy.
• Demonstrated feasibility of periodic BE-CCSD for large, complex donor-acceptor polymers relevant to organic solar cells.
• Overcame computational limitations where even a single k-point (Γ-point) CCSD calculation is prohibitive.

Conclusions:

• Bootstrap embedding is a promising tool for applying molecular electronic structure methods to solids and interfaces.
• Periodic BE offers a computationally efficient approach for accurate electronic structure calculations of extended systems.
• This method facilitates the study of complex materials, such as those used in organic solar cells.