The solution of tetrabutylammoniumiodide in formamide: investigation of the surface by MIES

The authors have studied the surface of the solution of tetrabutylammoniumiodide (TBAI) in formamide (FA). The extreme surface sensitivity of metastable impact electron spectroscopy allows them to state that the anions I - are part of the topmost layer. This was not unambiguously predictable from previous experiments and not borne out by standard model concepts. The model that they propose on the basis of their own and published data characterizes the surface at high concentrations as dominated by two-dimensional TBAI clusters. These clusters begin to form at molalities around 0.1 and are sensitive to temperature before they stabilize at higher molal concentrations.