Oxide Surface Structure and Acidity
EMSL Project ID
19838
Abstract
If we are to understand interfacial geochemical reactions on a molecular scale and apply the insights we gain to field-scale modeling, we must find ways to integrate the results of molecular-scale studies into standard geochemical reaction codes. Multisite complexation (MUSIC) models are one way to do this, but over the past few years, EMSL scientist Kevin Rosso and I have shown that the standard method for predicting surface acidity constants (pKa values) for MUSIC models is deeply flawed. In its place, we have developed a new method for predicting pKa values that involves ab initio structure calculations, and takes into account both bond relaxation effects and non-ideality in the local electric field. Our method has been tested extensively on (hydr)oxy-acid solution monomers, and on a few surfaces with good success. However, the next step in the development of our model is to fully account for solvation effects using ab initio molecular dynamics (AIMD) simulations of solvated surfaces. Once again, we have already extensively tested these calculations with solution monomers, with excellent success. Here we propose to continue the relationship between BYU Geological Sciences and the EMSL, with Kevin Rosso running the needed calculations using EMSL facilities.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2006-07-21
End Date
2008-12-04
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Bickmore BR, KM Rosso, ID Brown, and SN Kerisit. 2009. "Bond-Valence Constraints on Liquid Water Structure." Journal of Physical Chemistry A 113(9):1847-1857.