Excitation spectra of fully correlated donor-acceptor complexes by density matrix renormalisation group

Abstract

In this paper, we investigate the convergence properties of density matrix renormalisation group (DMRG) calculations for vertical electronic excitations performed on three bimolecular complexes motivated by Szalay's recent benchmark results [JCTC. 2020;16:7]. Besides the high-level coupled-cluster reference spectrum, the extrapolated truncation-free DMRG results are compared against several alternative solutions based on multireference configuration interaction and coupled-cluster theories. By taking advantage of the error cancellation effects, which are inherent in the state-averaged computational scheme, we demonstrate that the extrapolated solution based on only low bond-dimensional DMRG data could already provide quantitative predictions even for large active spaces. We also show that orbital optimisation improves further the accuracy of the DMRG results which systematically approach the excitation energies of coupled cluster single-double-triple at similar computational costs.

GRAPHICAL ABSTRACT

Keywords:

• Density matrix renormalization group
• charge transfer excitation
• excited states

Acknowledgments

This paper is dedicated to Péter Szalay on the occasion of his 60th birthday. A.P. is grateful to Péter Szalay for the continuous fruitful discussions on the correlated electronic structure methods. G.B. and A.P. contributed equally to this work.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Ministry of Innovation and Technology and the National Research, Development and Innovation Office of Hungary (NKFIH) within the Quantum Information National Laboratory, the National Excellence Program (project No. KKP129866) and project Nos. K134983, TKP2021-NVA and FK135496. Ö.L. also acknowledges financial support from the Hans Fischer Senior Fellowship programme funded by the Technical University of Munich – Institute for Advanced Study. The development of DMRG libraries has been supported by the Center for Scalable and Predictive methods for Excitation and Correlated phenomena (SPEC), which is funded as part of the Computational Chemical Sciences Program by the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences at Pacific Northwest National Laboratory. We acknowledge KIFÜ for awarding us access to computational resources based in Hungary.