Subsystem Density-Functional Theory as an Effective Tool for Modeling Ground and Excited States, their Dynamics, and Many-Body Interactions

TL;DR

Subsystem Density-Functional Theory (DFT) is a promising approach for modeling complex systems' electronic structures, excited states, and many-body interactions, with recent advances enhancing its practical and theoretical applications.

Contribution

This review highlights recent developments in subsystem DFT for condensed phase systems, excited states, and many-body interactions, including new results from the authors' research group.

Findings

Advances improve the practical applicability of subsystem DFT.

Subsystem DFT provides insights into quantum-mechanical phenomena.

Recent work demonstrates the method's effectiveness in complex systems.

Abstract

Subsystem Density-Functional Theory (DFT) is an emerging technique for calculating the electronic structure of complex molecular and condensed phase systems. In this topical review, we focus on some recent advances in this field related to the computation of condensed phase systems, their excited states, and the evaluation of many-body interactions between the subsystems. As subsystem DFT is in principle an exact theory, any advance in this field can have a dual role. One is the possible applicability of a resulting method in practical calculations. The other is the possibility of shedding light on some quantum-mechanical phenomenon which is more easily treated by subdividing a supersystem into subsystems. An example of the latter is many-body interactions. In the discussion, we present some recent work from our research group as well as some new results, casting them in the current state-of-the-art in this review as comprehensively as possible.