(663g) Force Fields for Layered Silicates and Metals

Authors: 
Heinz, H. - Presenter, Air Force Research Laboratory
Vaia, R. A. - Presenter, Wright Patterson Air Force Research Laboratory
Farmer, B. L. - Presenter, Air Force Research Laboratory
Koerner, H. - Presenter, Air Force Research Laboratory


A major challenge in computational chemistry and materials science is the simulation of hybrid systems such as bioorganic-inorganic and organic-inorganic interfaces. Many force fields have the capability to deal with biologically oriented or common organic molecules, but compatible energy models of good quality for inorganic components such as silicates or metals are still scarce. Successful concepts to develop such models will be outlined for the example of sheet silicates and fcc metals. An important aspect is the accurate reproduction of experimental values of surface tensions in the models (both solid-solid and solid-liquid) to be able to reproduce interfacial properties in hybrid materials (e.g., composites and bioinspired materials) in a simulation. We illustrate that this aspect has received only marginal consideration in both open source and commercially available force fields, and that common energy expressions (PCFF, CVFF, CHARMM, GROMACS) are capable of quantitatively reproducing surface properties when parameterizations are carried out strictly according to physical guidelines. Accurate force fields for mica-type silicates and fcc metals are presented, which achieve quantitative agreement between computed and experimental surface tensions, as well as cell parameters. [1] H. Heinz, H. Koerner, K. L. Anderson, R. A. Vaia, B. L. Farmer, Chem. Mater. 2005, 17, 5658?5669.