Beyond Isolated-Molecule TDDFT: Solvation, Aggregation, and Interfacial Fields in Predicting Spectroscopic Signatures and Charge-Transfer Mechanisms – A Systematic Review

Density functional theory and time-dependent density functional theory are commonly used to interpret and predict spectroscopic properties of molecular and materials systems. However, a significant portion of TDDFT-based spectroscopic investigations still use isolated-molecule  approximations that cannot reproduce the decisive role that realistic environments often play. In this comprehensive literature review, we recapitulate recent advances in environment-resolved DFT/TDDFT spectroscopy, with particular focus on  the contributions of solvation, molecular aggregation, and interfacial electric fields to spectral signatures and charge-transfer mechanisms. In accordance with a PRISMA-style review design, the analysis of 83 peer-reviewed studies generated  from all major application areas (such as molecular chromophores, fluorescent sensors, photoactive materials, supramolecular assemblies, nanoclusters, and hybrid interfaces). The findings emphasize that environmental interactions are not secondary perturbations but profoundly influence the excited-state electronic structure, often leading  to qualitative changes in spectral features and mechanistic insights. Key studies in the surveyed literature consistently  indicate that explicit microsolvation, aggregation modeling, and interface- and field-resolved methods improve spectroscopic fidelity to isolated-molecule models. This review lays out a comprehensive framework for environment-resolved computational spectroscopy and highlights many methodological gaps, e.g., disparate validation and the lack of consideration  of collective and interfacial effects. In this paper, we aim to advance DFT/TDDFT spectroscopy toward predictive reliability and quantitative accuracy for complex molecular and materials systems by outlining best-practice recommendations and future research directions.