Efficiently computing excitations of complex systems: linear-scaling time-dependent embedded mean-field theory in implicit solvent

TL;DR

This paper introduces a linear-scaling, time-dependent embedded mean-field theory method combined with implicit solvent models, enabling efficient and accurate electronic excitation calculations on large complex systems.

Contribution

It extends TD-EMFT with linear-scaling DFT and implicit solvation, allowing large-scale multi-level excitation calculations with environmental effects.

Findings

Successfully applied to molecular dimer, chromophore in solution, and doped crystal.

Demonstrates feasibility of high-accuracy excitations on large systems.

Reduces computational cost while maintaining accuracy.

Abstract

Quantum embedding schemes have the potential to significantly reduce the computational cost of first principles calculations, whilst maintaining accuracy, particularly for calculations of electronic excitations in complex systems. In this work, I combine time-dependent embedded mean field theory (TD-EMFT) with linear-scaling density functional theory and implicit solvation models, extending previous work within the ONETEP code. This provides a way to perform multi-level calculations of electronic excitations on very large systems, where long-range environmental effects, both quantum and classical in nature, are important. I demonstrate the power of this method by performing simulations on a variety of systems, including a molecular dimer, a chromophore in solution, and a doped molecular crystal. This work paves the way for high accuracy calculations to be performed on large-scale systems that were previously beyond the reach of quantum embedding schemes.