Fully self-consistent GW calculations for molecules

By C. Rostgaard, K. Wedel, Thygesen, K. Sommer. 2010

195 citations recorded by the source corpus.

We calculate single-particle excitation energies for a series of 33 molecules using fully selfconsistent GW, one-shot G$_0$W$_0$, Hartree-Fock (HF), and hybrid density functional theory (DFT). All calculations are performed within the projector augmented wave (PAW) method using a basis set of Wannier functions augmented by numerical atomic orbitals. The GW self-energy is calculated on the real frequency axis including its full frequency dependence and off-diagonal matrix elements. The mean absolute error of the ionization potential (IP) with respect to experiment is found to be 4.4, 2.6, 0.8, 0.4, and 0.5 eV for DFT-PBE, DFT-PBE0, HF, G$_0$W$_0$[HF], and selfconsistent GW, respectively. This shows that although electronic screening is weak in molecular systems its inclusion at the GW level reduces the error in the IP by up to 50% relative to unscreened HF. In general GW overscreens the HF energies leading to underestimation of the IPs. The best IPs are obtained from one-shot G$_0$W$_0$ calculations based on HF since this reduces the overscreening. Finally, we find that the inclusion of core-valence exchange is important and can affect the excitation energies by as much as 1 eV.

Subfields: Atomic and Molecular Physics, and Optics, Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/c7aa59441b53d7a656d0fbe3adc9c8cf84d011da

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In Atomic and Molecular Physics, and Optics

In Electrical and Electronic Engineering

Citations in the corpus

Calculating excitons, plasmons, and quasiparticles in 2D materials and van der Waals heterostructures (2017, background): “GW calculations of freestanding 2D materials The performance of the GW approximation has been thoroughly established for bulk materials [56–58] and more recently also for molecules [59, 60].”
GW method and Bethe–Salpeter equation for calculating electronic excitations (2016, background): “Caruso et al. studied the same set of molecules as Rostgaard et al.54 in 2012 and got a conflicting conclusion.66 They argued that full scGW improves IP systematically compared to G0W0-HF.”
Electronic structure calculations with GPAW: a real-space implementation of the projector augmented-wave method (2010, methodology): “In GPAW, these functions are used as an efficient minimal basis set for performing computationally demanding GW calculations [53].”