(189ba) Benchmarks for Adsorption on Transition Metal Oxide Surfaces: A Comparison of DFT to Experimental Data for NH3 on MnO(100)

Density functional theory (DFT) is commonly used to investigate adsorption and reaction processes on surfaces. While it is widely used, the applicability of DFT to highly correlated transition metal oxide systems with unpaired d-electrons is problematic, especially when using plane wave basis sets. A primary issue is the lack of quality experimental data for adsorbate and reaction systems on well-defined (single crystal) transition metal oxide surfaces to provide benchmarks for the applicability of current DFT methods and the future development of new methods. We have established experimental benchmarks using temperature programmed desorption (TPD) for the adsorption energy of ammonia molecules (NH₃) on MnO(100) for comparison to DFT simulations on terraces, using Perdew-Burke-Ernzerhof (PBE) functionals with DFT+U, in conjunction with a number of Van der Waals force correction packages.