Theoretical Studies of Etching and Growth Dynamics at Surfaces

With support from this grant in the Theoretical and Computational Chemistry program, Dr. Garrison will investigate, via molecular dynamics simulations, the reactions of gases with solid surfaces in order to gain a microscopic and fundamental understanding of the atomic motions involved. Emphasis will be placed on reactions that involve either the growth or destruction (etching) of the solid itself. A fundamental understanding of this process is needed for the interpretation of experimental data ranging from the energy and angular distributions used in determining surface structures to the fragmentation patterns observed in the ejection process when large biomolecules are bombarded. To realistically model these processes, however, it will first be necessary to unify the description of the many-body interaction potentials or force fields for these systems. Hence, Dr. Garrison and her students will work on this problem by studing specific rhodium surfaces. The relationship between the microscopic motion of atoms during chemical reactions at crystal surfaces and macroscopic observables such as reaction rates has been sought by experimentalists and theoreticians alike for the last several decades. The development of such a relationship has been difficult for each research community. Techniques for performing well-defined experiments at surfaces are only recently being perfected. Theoretical methods for examining detailed reaction mechanisms are dependent upon the availability of reliable manybody interaction potentials. Ab initio methods which can be successfully applied to define and the interaction between small numbers of atoms become cumbersome and computationally prohibitive for large ensembles of atoms. Dr. Garrison expects to develop new theoretical approaches which may be applied to describing chemical reactions which occur at solid surfaces with an emphasis on those processes that involve either the growth or destruction of the solid itself.