Renormalized Singles Green's Function in the T-Matrix Approximation for Accurate Quasiparticle Energy Calculation

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Electronic Structure Theory

Background:

• Accurate computation of quasiparticle energies is crucial for understanding molecular properties.
• Existing methods like G0T0 and G0W0 have limitations in accuracy and dependence on approximations.
• Renormalized singles (RS) Green's function offers improved description of electronic correlations.

Purpose of the Study:

• To develop and validate a new computational method for calculating quasiparticle energies in molecular systems.
• To improve the accuracy of electronic structure calculations for both valence and core states.
• To reduce the dependence of calculations on the choice of density functional approximations.

Main Methods:

• Combining the renormalized singles (RS) Green's function with the T-matrix approximation.
• Introducing the GRST0 and GRSTRS methods.
• Utilizing RS eigenvalues in T-matrix calculations via particle-particle random phase approximation.

Main Results:

• The GRSTRS method shows significant improvements over G0T0 and G0W0 for GW100 and CORE65 test sets.
• GRSTRS eliminates the dependence of G0T0 on density functional approximations.
• GRSTRS achieves excellent accuracy for valence states and correctly identifies spectral function peaks for core states.

Conclusions:

• The GRSTRS method provides a highly accurate and reliable approach for computing quasiparticle energies.
• GRSTRS outperforms previous methods for both valence and core electronic states.
• This advancement offers a more robust tool for theoretical chemistry research.