Density Matrix Renormalization Group embedding in Kohn-Sham orbital environment

The density matrix renormalization group (DMRG) method has already proved itself a very accurate computational method, which can treat large active spaces and capture the major part of strong correlation. Its application on larger molecules is, however, limited by its computational scaling. DFT approximations, on the other hand, allow for efficient calculations of electronic structure but they struggle in description of strong correlation. We present the first step in the direction of combining DMRG with density functional theory (DFT) by means of embedding DMRG in the orbital environment.

Comparing with the orbital-free-embedding, the orbital-environment-embedding does not involve nonadditive kinetic energy functional. Yet, the nonadditive exchange-correlation functional is of high importance as it describes subsystem-environment correlations. We propose a nonlocal random-phase-approximation-based correction to the nonadditive correlation functional.

We demonstrate that the developed DMRG-in-DFT approach provides a very accurate description of molecules with a strongly correlated fragment.



[1] P. Beran, K. Pernal, F. Pavosevic, L. Veis, arXiv:2210.16289 (2022) (submitted)