An O(N3) implementation of Hedin's GW approximation for molecules.

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Materials Science

Background:

• Accurate prediction of molecular electronic properties is crucial for materials discovery.
• Existing methods for electronic structure calculations often face scalability challenges with increasing system size.

Purpose of the Study:

• To develop and implement an efficient computational approach based on Hedin's GW approximation.
• To enable accurate prediction of ionization energies and electron affinities for large molecules.

Main Methods:

• Implementation of Hedin's GW approximation with O(N^3) scaling.
• Utilizing local atomic orbital bases and product spaces to exploit electronic interaction locality.
• Employing spectral functions and fast Fourier transform methods to handle Green's function singularities.
• Compressing the screened Coulomb interaction to reduce computational cost and memory usage.

Main Results:

• Achieved a computational complexity that scales favorably with the number of atoms (O(N^3)).
• Demonstrated an efficient method for handling electronic interactions and Green's function singularities.
• Reduced memory requirements and improved computational speed through interaction compression.

Conclusions:

• The developed GW approximation implementation offers improved scalability for large molecular systems.
• This advancement facilitates more accurate predictions of electronic properties for organic semiconductor constituents.
• The method serves as a step towards designing novel materials prior to synthesis.