Optimized virtual orbital subspace for faster GW calculations in localized basis

Area of Science:

• Computational Chemistry
• Quantum Mechanics
• Materials Science

Background:

• The GW approximation is increasingly popular for calculating molecular quasiparticle energies.
• Slow convergence of the GW self-energy with basis set complexity limits its application to large molecules.

Purpose of the Study:

• To develop a method for accurate and efficient calculation of quasiparticle energies for large molecules using the GW approximation.
• To mitigate the slow convergence issue of the GW self-energy.

Main Methods:

• A two-step approach involving a reduced virtual orbital subspace with a smaller basis set.
• Accounting for the remainder of the self-energy using the one-ring approximation.

Main Results:

• The proposed method yields corrected quasiparticle energies of good quality for simple molecules.
• Demonstrated numerical efficiency of the scheme for large graphene chunks.

Conclusions:

• The developed method effectively improves the accuracy and efficiency of GW calculations for large molecular systems.
• This approach offers a practical solution for studying electronic properties of complex materials.