Glancing-angle Raman study of nitrate and nitric acid at the air–aqueous interface
Sumi N. Wren, D.J. Donaldson
Chemical Physics Letters 522 (2012) 1–10
Glancing-angle Raman spectra of aqueous KNO3 and HNO3 solutions were measured to determine the degree of nitric acid dissociation in the bulk and in the surface region. Acid dissociation in the surface region is similar to that in the bulk and depends strongly on water molecule availability to the dissociation process. The spectra were used to construct an adsorption isotherm for nitrate anion at the water surface; it exhibits an almost neutral surface affinity.