Assessing frequency-dependent site polarisabilities in linear response polarisable embedding

ABSTRACT

In this paper, we discuss the impact of using a frequency-dependent embedding potential in quantum chemical embedding calculations of response properties. We show that the introduction of a frequency-dependent embedding potential leads to further model complications upon solving the central equations defining specific molecular properties. On the other hand, we also show from a numerical point of view that the consequences of using such a frequency-dependent embedding potential is almost negligible. Thus, for the kind of systems and processes studied in this paper the general recommendation is to use frequency-independent embedding potentials since this leads to less complicated model issues. However, larger effects are expected if the absorption bands of the environment are closer to that of the region treated using quantum mechanics.

KEYWORDS:

• Frequency-dependent embedding potential
• QM/MM embedding
• distributed polarisabilities
• response properties

Acknowledgments

This paper is dedicated to Professor Hans Jørgen Aagaard Jensen on the occasion of his 60th birthday. The authors deeply acknowledge the important contributions made by Hans Jørgen to the field of computational quantum chemistry and thank him for many years of great inspiration and an extremely friendly and open-minded attitude. We further thank Joanna Kauczor for discussions on code modifications required for this work.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

Danish Councils for Independent Research (DFF) [grant number FI-0602-02122B]; Villum Foundation; DeIC National HPC Center, SDU; Swedish Research Council [grant number 621-2014-4646].