Статья

Electron Spectroscopy of Aqueous Solution Interfaces Reveals Surface Enhancement of Halides

Sutapa GhosalAdvanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USAJohn C. HemmingerAdvanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USAHendrik BluhmAdvanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USABongjin Simon MunAdvanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USAE.L.D. HebenstreitAdvanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USAGuido KettelerAdvanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USAD. Frank OgletreeAdvanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USAFélix G. RequejoAdvanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USAMiquel SalmerónAdvanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA

2005en

ABI

Аннотация

It has been suggested that enhanced anion concentrations at the liquid/vapor interface of airborne saline droplets are important to aerosol reactions in the atmosphere. We report ionic concentrations in the surface of such solutions. Using x-ray photoelectron spectroscopy operating at near ambient pressure, we have measured the composition of the liquid/vapor interface for deliquesced samples of potassium bromide and potassium iodide. In both cases, the surface composition of the saturated solution is enhanced in the halide anion compared with the bulk of the solution. The enhancement of anion concentration is more dramatic for the larger, more polarizable iodide anion. By varying photoelectron kinetic energies, we have obtained depth profiles of the liquid/vapor interface. Our results are in good qualitative agreement with classical molecular dynamics simulations. Quantitative comparison between the experiments and the simulations indicates that the experimental results exhibit more interface enhancement than predicted theoretically.

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Идентификаторы

DOI: 10.1126/science.1106525

Цитирования и источники

Цитирований: 2Использованных источников: 0

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