Charge transfer reaction at gas-liquid interface of aqueous tetrabutylammonium iodide solution: influence of ions on dynamical response of solvent

Tetrabutylammonium iodide (TBAI) is known to create an electric double layer at the air-water interface. In the present study, we investigated the charge-transfer-to-solvent reaction from iodide ions to liquid water near the gas-liquid interface of an aqueous TBAI solution using extreme UV (EUV) time-resolved photoelectron spectroscopy. Use of EUV radiation ensured accurate measurements of electron kinetic energy distributions by minimizing spectral distortions caused by electron inelastic scattering in the liquid and the influence of the electron transmission efficiency through the gas-liquid interface. The spectra observed for photodetached electrons exhibited a rapid energy shift and a variation of the bandwidth in subpicoseconds, and the rates of these changes clearly depended on the TBAI concentration. The results indicate that the dynamical response of solvent water changes in the presence of a high density of ions. We investigated the charge-transfer-to-solvent reaction from iodide ions to liquid water near the gas-liquid interface of an aqueous TBAI solution using extreme UV (EUV) time-resolved photoelectron spectroscopy. Use of EUV radiation ensured accurate measurements of electron kinetic energy distributions by minimizing spectral distortions caused by electron inelastic scattering in the liquid and the influence of the electron transmission efficiency through the gas-liquid interface. The spectra observed for photodetached electrons exhibited a rapid energy shift and a variation of the bandwidth in subpicoseconds, and the rates of these changes clearly depended on the TBAI concentration. The results indicate that the dynamical response of solvent water changes in the presence of a high density of ions.