2010/01/08 by C. Rostgaard, Karsten W. Jacobsen, K. W. Jacobsen +2 · 5 citations
Engineering · Physics and Astronomy · #Advanced Chemical Physics Studies #Atomic orbital #Atomic physics #Basis set #Density functional theory #Excitation #Ion #Ionization #Ionization energy #Molecular Junctions and Nanostructures #Physics #Quantum mechanics #Spectroscopy and Quantum Chemical Studies #Valence (chemistry) #cond-mat.mes-hall #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.81.085103
10 pages, 5 figures
arxiv created 2010/01/08 · openalex publication_date 2010/02/03 · arxiv updated 2015/05/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We calculate single-particle excitation energies for a series of 34 molecules using fully self-consistent GW, one-shot G0W0, Hartree-Fock (HF), and hybrid density-functional theory (DFT). All calculations are performed within the projector-augmented wave 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, G0W0[HF], and self-consistent 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 G0W0 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.