Relativistic Fully Self-Consistent GW for Molecules: Total Energies and Ionization Potentials

Area of Science:

• Quantum chemistry
• Computational physics
• Materials science

Background:

• The GW approximation is a powerful tool for electronic structure calculations.
• Relativistic effects are crucial for heavy elements.
• Self-consistency in GW calculations removes dependence on initial approximations.

Purpose of the Study:

• To develop and validate a relativistic, fully self-consistent GW (scGW) method for molecules with heavy elements.
• To benchmark the accuracy of scGW against experimental data and other GW approximations.
• To assess the performance of scGW for ionization potentials, photoelectron spectra, and total energies.

Main Methods:

• Implementation of a relativistic scGW method using the exact two-component (X2C) Coulomb approximation.
• Benchmarking against the SOC-81 dataset for first ionization potentials.
• Comparison with one-shot GW (G0W0) using PBE and PBE0 references.
• Calculation of photoelectron spectra and analysis of total energies for molecular properties.

Main Results:

• Relativistic scGW provides accurate ionization potentials for heavy elements, outperforming G0W0 with PBE and matching G0W0 with PBE0 without starting point dependence.
• Calculated photoelectron spectra show excellent agreement with experimental data.
• scGW accurately estimates ionization potentials for inner d-shell orbitals.
• Total energies calculated using scGW are reliable for investigating molecular geometries and vibrational frequencies.

Conclusions:

• The relativistic scGW method is a robust and accurate approach for electronic structure calculations of systems containing heavy elements.
• This method offers significant improvements in predicting ionization potentials and photoelectron spectra.
• scGW presents a viable computational tool with reasonable scaling for complex molecular systems.