Dehydration of iodide segregated by tetraalkylammonium at the air/solution interface studied by photoelectron emission spectroscopy

Photoelectron emission spectroscopy was used to detect iodide anion at the aqueous solution surface. The photoelectron emission threshold energies Et for the iodide segregated by tetraalkylammonium cations differ from those for solutions with surface inactive cations. The smaller Et values found for larger alkylammonium salt solutions seem to be due to dehydration of iodide at the surface layer. When tetrabutylammonium is used as the surfactant, the dehydration proceeds in a stepwise way with increasing bulk concentration.