Abstract
<jats:p>Phenol aggregate populations in carbon tetrachloride are governed by an enthalpyentropy balance that varies with concentration and temperature. This redistribution is reflected in the infrared O H stretching band, whose position and shape provide a sensitive test for population models. Here, monomer-to-tetramer populations are determined over a concentration–temperature grid using two strategies that share the same graphbased aggregate classification: a cluster-based approach relying on partition functions from conformational-search structures, and a trajectory-derived approach extracting populations from molecular dynamics simulations. The latter reproduces the experimental attenuation and displacement of the aggregate-associated bands, especially in concentrated solutions, whereas the cluster-based model predicts an overly sharp thermal depletion of larger aggregates. Temperature-dependent data further enable van’t Hoff estimates of aggregation enthalpies and entropies. Comparison with experiment shows that the trajectory-derived strategy captures aggregation thermodynamics across the aggregate series supporting a better sampling of the configurational space.</jats:p>