POLAR ORDERING AT THE LIQUID-VAPOR INTERFACE OF N-ALCOHOLS (C-1-C-8)

Vibrational spectra of the liquid-vapor interfaces of methanol, ethano l, propanol, butanol, pentanol, hexanol, heptanol and octanol were obt ained in the CH and OH stretching region using infrared-visible sum-fr equency generation. All alcohols studied are polar oriented at such in terfaces with the alkyl chain pointing away from the liquid. For hexan ol, heptanol, and octanol, the spectra show the presence of trans-gauc he defects in the alkyl chain. For all alcohols, the shift of spectra to lower frequency in the OH stretching region indicates a well-ordere d hydrogen-bonding network at the interface.