Polarization Energies from Efficient Representation of the Linear Density–Density Response Function

Abstract

The authors present a proof‐of‐concept study for the calculation of atomic forces on a solvated molecule by means of the linear density–density response function in its moment expanded representation. The density–density response function represents an efficient way to compute molecular forces for arbitrary external potentials via an ab initio scheme, without the need to perform an explicit self‐consistent quantum chemical calculation for each configuration of the chemical environment. Here, the authors show that it is indeed possible to determine the atomic forces of interacting bulk‐like molecular complexes due to polarization effects of the surrounding molecules with good accuracy. This study represents a significant step the practical applicability of the approach, which is still in a development phase. The potential application of the computational scheme in terms of molecular dynamics simulations is illustrated by considering a variety of cluster conformations, as they would be found within a molecular dynamics trajectory.

Subsystem-Based GW/Bethe–Salpeter Equation

“…All in all this work provides a transferable and efficient fragmentation method for GW and BSE based on sDFT, which does not rely on additional parametrization, and is capable of describing quasi-particle energies and excitation energies accurately for a specific region of interest within a complex chemical environment. Possible further improvements and efficiency enhancements of the presented methodology can be gained by approximating the full environmental polarizability by means of an efficient representation through a moment expansion as recently demonstrated by Sebastiani and co-workers. − …”