Statistical Analysis of Tri-Cresyl Phosphate Conversion on an Iron Oxide Surface Using Reactive Molecular Dynamics Simulations

Parallel reactive molecular dynamics simulations were used to statistically analyze chemical reactions between tri-cresyl phosphate (TCP) and an amorphous iron oxide surface. To accurately model this system, a new parameter set for Fe/P/O interactions within the ReaxFF framework was developed. Using the new parameter set, 100 parallel simulations of a single TCP molecule on an amorphous iron oxide surface were run to capture multiple possible reactions at temperatures ranging from 300 to 700 K. The frequency of TCP-surface reactions for each atom type and each unique reaction site on the TCP was analyzed across the range of temperatures. Finally, the composition of the material chemisorbed to the surface was determined and analyzed in the context of previously reported experimental measurements of TCP films in oxygen-deficient environments. The results are specifically relevant to TCP, but the parallel reactive simulation approach and statistical analysis of reaction sites can be applied more generally to a range of chemical systems, particularly those involving complex molecules and disordered surfaces where many different reactions are possible.