K. Das et al., SALT EFFECT ON P-NITROPHENOL AT THE WATER-SURFACE - A SURFACE 2ND-HARMONIC GENERATION STUDY, Journal of the Chemical Society. Faraday transactions, 92(24), 1996, pp. 4993-4996
Citations number
39
Categorie Soggetti
Chemistry Physical","Physics, Atomic, Molecular & Chemical
The effect of lithium perchlorate (LiClO4), guanidinium hydrochloride
(GdmCl) and lithium chloride (LiCl) on the resonance surface second ha
rmonic generation (SSHG) of p-nitrophenol (PNP) at the air/water inter
face is reported. On addition of GdmCl and LiClO4 the intensity of the
SSH signal decreases appreciably, which is attributed to the decrease
in surface population of PNP. Addition of LiCl causes an increase in
the intensity of SSHG due to increase in surface population. The orien
tation of the PNP molecules remains unchanged on addition of all the s
alts. The free energy of adsorption (Delta(ad)G) of PNP increases upon
addition of the salting-in agents, but decreases for the salting-out
agent. The results indicate that the factors which increase solubility
of organic solutes in the bulk decrease the surface population of org
anic molecules at the surface and vice versa.