Studies of liquid surfaces by second harmonic generation

Information on the orientation and relative composition of solute molecules at the surface of a liquid solution has been obtained by the technique of second harmonic generation. In an aqueous phenol solution, the phenol molecules at the vapor/solution interface are found to be oriented with their long axes tilted 50° from the surface normal. The orientation is found to be insensitive to the concentration of the phenol solution. A comparison with surface concentration information obtained from surface tension data is made. © 1986 American Chemical Society.