Computational Solid State Chemistry Group Steve Parker Dept of Chemistry University of Bath

Steve Parker Dept of Chemistry University of Bath Molecular Simulation of minerals and their interfaces Using computational methods to understand the factors controlling structure, composition and reactivity of minerals at the ATOMIC level.

Current projects that complement new project Simulation of Composition –Surface phase diagrams –Ab initio techniques Modelling the structure of solid-liquid interface at high ionic strengths Calculation of rates of adsorption and desorption –classical molecular dynamics –Importance of electronic polarisability

Example 1 Surface Composition –Ab Initio Favours dissociatively adsorbed water Trainor T.P., Surf. Sci. (2002) A. Marmier  -Alumina (01.2)

Example 2 Interface Structure - MD S. Kerisit + D Cooke & A. Marmier 1 M NaCl 1 M CsCl FeOOH project S Kerisit, D Cooke A Marmier

Example 3 Rate of Desorption + Adsorption Kerisit S. and Parker S.C., JACS Inner-sphere complex much lower in free energy 1 Inner-sphere complex 1 Outer-sphere complex Free energy barrier similar to that of calcium and strontium Ionk ads. /s -1 k des/ /s -1 Mg Calcium Carbonate

Project Targets Test – Refine – Extend Potential Models –Description of interatomic forces must be reliable. –Include all elements in expts Zeolite - Solution Interface –Surface structure –Surface composition –Both as a function of solvent and ionic strength Rates of Growth –Calculate formation of kinks, –free-energy of adsorption/desorption and Transmission coefficients = rate

Project Targets Test – Refine – Extend Potential Models –Description of interatomic forces must be reliable. –Include all elements in expts Zeolite - Solution Interface –Surface structure –Surface composition –Both as a function of solvent and ionic strength Rates of Growth –Calculate formation of kinks, –free-energy of adsorption/desorption and Transmission coefficients = rate

Project Targets Test – Refine – Extend Potential Models –Description of interatomic forces must be reliable. –Include all elements in expts Zeolite - Solution Interface –Surface structure –Surface composition –Both as a function of solvent and ionic strength Rates of Growth –Calculate formation of kinks, –free-energy of adsorption/desorption and Transmission coefficients = rate

Requirements From Other Groups –Targets –Morphologies –Surface structures From Exptal Groups –Well Characterised model systems –High quality data to compare – check – test nm nm