Fig. 5: Interfacial accumulation and stabilization.

a Gibbs free-energy profiles for the calculation of a HCHO molecule (red line) or a \({{{{\rm{HOSO}}}}}_{2}^{-}\) molecule (purple dash line) transferring from the bulk water to gas-phase. b Schematic figure of the distribution of the HCHO and the \({{{{\rm{HOSO}}}}}_{2}^{-}\) molecules in the bulk water and at the air-water interface. c Stacked histograms of the calculated entropy of the HCHO molecule, H₂O molecule, and the HCHO−H₂O complex. d Dipole autocorrelation function (dots) and the fitted curve (lines) for pure water (grey line), a HCHO molecule in the aqueous system (blue dash line), and a HCHO molecule at the air-water interface (red line). The histograms represent the correlation time for each system. e Angular distribution profile (0–360°) for the angle between the C=O direction vector and x, y, z axis in the bulk water (blue dash lines) and at the air-water interface (red lines). f Snapshot of the θ_z = 90° of HCHO at the air-water interface.