Ion adsorption to the surfaces of liquid electrolytes: Beyond Langmuir and Onsager

COLL 381

Richard J. Saykally, saykally@berkeley.edu, Department of Chemistry, University of California, Berkeley, CA 94720-1460
We have recently verified theoretically predicted surface enhancement for a number of small ions, including iodide, azide, thiocyanate and ferrocyanide, in a series of femtosecond UV second harmonic generation experiments, which demonstrated Langmuir adsorption behavior of the ions and yielded free energies of adsorption that were generally larger than predicted values.

Following theoretical predictions that the hydronium ion is also enhanced at the liquid water surface, we have performed comparative studies of iodide adsorption in salts and acids that support this predicted enhancement.

We have also verified the Jones-Ray Effect for alkali iodide and potassium ferrocyanide solutions by UV femtosecond SHG experiments, which reveal an initial surface enhancement, followed by a depletion at higher concentrations.

 

Water at Interfaces
8:30 AM-11:40 AM, Tuesday, 12 September 2006 Sir Francis Drake -- Tudor Room, Oral

Division of Colloid & Surface Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006