GW with hybrid functionals for large molecular systems

TL;DR

This paper introduces a low-cost stochastic method for GW calculations in large molecular systems, leveraging hybrid DFT starting points and generalized Kohn-Sham orbitals to improve efficiency and accuracy.

Contribution

It presents a novel stochastic GW approach that reduces computational cost and starting point dependency using hybrid functionals and generalized Kohn-Sham orbitals.

Findings

Enables efficient GW calculations for large molecules.

Reduces need for self-consistent GW iterations.

Improves accuracy with hybrid DFT starting points.

Abstract

A low-cost approach for stochastically sampling static exchange during TDHF-type propagation is presented. This enables the use of an excellent hybrid DFT starting point for stochastic GW quasiparticle energy calculations. Generalized Kohn-Sham molecular orbitals and energies, rather than those of a local-DFT calculation, are used for building the Green's function and effective Coulomb interaction. The use of an optimally tuned hybrid diminishes the starting point dependency in one-shot stochastic GW, effectively avoiding the need for self-consistent GW iterations.