Deciphering Infrared Spectra in TBA-CCl₄ Mixtures via a Hybrid MD-DFT Framework.

mixtures, it shows that the concentration-dependent IR changes are governed by the redistribution of cluster populations rather than simple hydrogen-bond weakening. Experimentally, this evolution is reflected mainly in band-shape changes and the gradual emergence of a high-frequency shoulder. Furthermore, we demonstrate that the complex features in the excess IR spectra arise not from a single dominant species but from the cooperative contributions of multiple coexisting hydrogen-bonded networks, specifically the competitive balance between the formation of small chain oligomers and the dissociation of large size clusters. This spectroscopically driven strategy provides a robust tool for deconvoluting molecular-level heterogeneity in complex condensed phases, effectively bridging the gap between atomistic simulations and spectroscopic observables.