Contrasting current textbook descriptions, a consistent picture of substantial 
concentration enhancement of highly polarizable anions at the surface of 
aqueous electrolyte solutions is emerging. Such enhancement may have important 
implications for chemistry occurring on aqueous aerosols and ocean surfaces. 
Here we present a combined experimental and theoretical investigation of the 
liquid/air interface of aqueous sodium thiocyanide at varying salt 
concentrations. Normalized second harmonic generation intensities fitted to 
Langmuir isotherms yield a Gibbs free energy of adsorption of -1.80 kcal/mol. 
These results are in accord with molecular dynamics simulations in slab 
geometry, which predict an appreciable surface enhancement of SCN-.