Extrapolating unconverged GW energies to the complete basis set limit with linear regression

Fabien Bruneval (1) , Ivan Maliyov (1) , Clovis Lapointe (1) , Mihai Cosmin Marinica (1)

1 SRMP - Service de recherches de métallurgie physique

The GW approximation to the electronic self- energy is now a well-recognized approach to obtain the electron quasiparticle energies of molecules and in particular their ionization po- tential and electron affinity. Though much faster than the corresponding wavefunction methods, the GW energies are still affected by a slow convergence with respect to the basis completeness. This limitation hinders a wider application of the GW approach. Here we show we can reach the complete basis set limit for the cumbersome GW calculations solely based on fast preliminary calculations with an unconverged basis set. We introduce a lin- ear model that correlates the molecular orbital characteristics and the basis convergence er- ror for a large database of about 600 states in 104 organic molecules that contain H, C, O, N, F, P, S, and Cl. The model employs molecular-orbital-based non-linear descriptors that encode efficiently the chemical space offer- ing an outstanding transferability. Using a low number of descriptors (17) the performance of this extrapolation procedure is superior to the earlier more physically-motivated approaches. The predictive power of the method is finally demonstrated for a selection of large acceptor molecules.

Domains: Theoretical and/or physical chemistry

Fabien Bruneval, Ivan Maliyov, Clovis Lapointe, Mihai Cosmin Marinica. Extrapolating unconverged GW energies to the complete basis set limit with linear regression. Journal of Chemical Theory and Computation, 2020, 16, pp.4399. ⟨10.1021/acs.jctc.0c00433⟩. ⟨cea-02931757⟩