Structural vs. Dynamical Estimators of the Excess Entropy of Water Across Its Phase Diagram: data and analysis scripts

Data, simulation inputs, and figure-generation scripts supporting Structural vs. Dynamical Estimators of the Excess Entropy of Water Across Its Phase Diagram (Do, Johnson & Pascal). The study compares the two-phase thermodynamics (2PT) excess entropy, a dynamical estimator built from the velocity-autocorrelation spectrum, against the two-body approximation S2, a structural estimator built from the pair-correlation function, for four rigid and flexible water models (SPC/E, TIP4P/2005, TIP4P/2005f, TIP4P/ICE) over a 220–360 K, 0.85–1.3 g/cm3 grid spanning the supercooled and compressed liquid. The archive contains, for every model and state point, the per-window liquid, ideal-gas and excess entropies, the two-body translational, orientational and total entropies, the offset-corrected values, and the number of trajectory windows retained; the vibrational density of states at five representative state points per model; a comparison of quantum against classical weighting of the solid-like density of states; and the LAMMPS and 2PT input files needed to regenerate the trajectories. Each entropy file carries one row per independent 200 ps trajectory window rather than one row per state point, so means, standard deviations and window counts are recoverable. Two IAPWS-95 reference tables are deposited. The original evaluation flashed to a two-phase mixture wherever the requested density fell inside the vapour–liquid envelope, returning the saturated-liquid entropy rather than the entropy at that density. The corrected table classifies all 70 state points: 26 valid, 9 re-referenced onto the mechanically stable stretched-liquid branch, 12 beyond the liquid spinodal where no homogeneous-liquid reference exists, and 23 retained as flagged extrapolations. The largest deviation between S2 and the reference falls from 4.058 to 1.995 kB once the unphysical points are removed; the 2PT side is unchanged. The included script regenerates main-text Figures 5 and 6 and SI Figure S7 from the deposited files alone, and carries a mode that reproduces the originally published artwork so it can be validated before the corrected reference is applied.