Calculating the Minimum Energy Crossing Point for Chemical Reactions with Intersecting Potential Energy Surfaces with Different Spin States
Arts and Sciences
For reactions with products in a different spin state than the reactants, the change of spin state along the minimum energy reaction pathway occurs at the minimum energy crossing point (MECP). This point is of particular interest for reactions where it dictates the activation energy required for the reaction. For such reactions, it is useful to determine the crossing point and its energy with precision. To accomplish this, a Python program was written to make calls to the Vienna ab-initio simulation package (VASP) electronic structure program. The energy and atomic forces for a particular molecular geometry in different spin states were calculated using VASP. These were used to iteratively update the geometry to approach the MECP using a previously published algorithm that was modified to work with VASP. In order to test the algorithm, results are presented and compared to previous MECP calculations. Finally, original MECP calculations are carried out for the propane dehydrogenation reaction catalyzed by transition metal atoms. These reactions are currently being studied in our research group in order to evaluate single-atom catalysts for propane dehydrogenation.
Bouman, Nathaniel I., "Calculating the Minimum Energy Crossing Point for Chemical Reactions with Intersecting Potential Energy Surfaces with Different Spin States" (2018). Symposium on Undergraduate Research and Creative Expression (SOURCE). 679.