GW100: A Plane Wave Perspective for Small Molecules

Abstract

In a recent work, van Setten and co-workers have presented a carefully converged GW study of 100 closed shell molecules [ J. Chem. Theory Comput. 2015 , 11 , 5665 - 5687 ]. For two different codes they found excellent agreement to within a few 10 meV if identical Gaussian basis sets were used. We inspect the same set of molecules using the projector augmented wave method and the Vienna ab initio simulation package (VASP). For the ionization potential, the basis set extrapolated plane wave results agree very well with the Gaussian basis sets, often reaching better than 50 meV agreement. In order to achieve this agreement, we correct for finite basis set errors as well as errors introduced by periodically repeated images. For positive electron affinities differences between Gaussian basis sets and VASP are slightly larger. We attribute this to larger basis set extrapolation errors for the Gaussian basis sets. For quasi particle (QP) resonances above the vacuum level, differences between VASP and Gaussian basis sets are, however, found to be substantial. This is tentatively explained by insufficient basis set convergence of the Gaussian type orbital calculations as exemplified for selected test cases.

Automation methodologies and large-scale validation for GW : Towards high-throughput GW calculations

“…34,39,40 For GW calculations on solids validation studies usually however restrict to one code and only a limited amount of systems. 33,[41][42][43] A systematic evaluation of the accuracy of the method is hence tedious at best.…”

Pros and Cons of the Bethe–Salpeter Formalism for Ground-State Energies

“…However, we also observe that, in some cases, unphysical irregularities on the ground-state PES, which are due to the appearance of a satellite resonance with a weight similar to that of the GW quasiparticle peak. [78][79][80][81][82] In order to compute the neutral (optical) excitations of the system and their associated oscillator strengths, the BSE expresses the two-body propagator 4,83 L(1, 2, 1 , 2 ) = L 0 (1, 2, 1 , 2 )…”

“…This shortcoming has been thoroughly described in several previous studies. [78][79][80][81][82] We believe that this central issue must be resolved if one wants to expand the applicability of the present method.…”

Legendre-spectral Dyson equation solver with super-exponential convergence

“…The algorithm is also relevant for condensed matter ab initio applications in periodic systems that require high precision, such as GF2 9-17 and Hedin's GW [18][19][20][21][22][23][24][25][26] . This is a promising venue for future research.…”