Figure 1

Upper panel: experimental $\mathrm{Im}({\chi }^{(2)})$ data (squares, reproduced from 1) along with models containing 2 (dashed line) and 3 (solid line) resonances in the H-bonded region of the spectrum. Lower panel: Although both models reproduce $\mathrm{Im}({\chi }^{(2)})$, it is impossible to obtain an adequate description of the SFG spectrum using two resonances, clearly indicative of the presence of 3 resonances in the spectrum.Reuse & Permissions