Dispersion corrected DFT calculations for the adsorption of N2O on MgO

We have calculated adsorption energies for N2O on the MgO (001) surface using periodic DFT calculations with the B3LYP functional and subsequent dispersion correction. Additionally a wave function-based correlation treatment at the MP2 level was performed. Whilst the B3LYP calculation failed to find a bond state, both the dispersion corrections and the MP2 treatment result in a significantly better description. The best agreement with experiment is obtained with a dispersion correction via the D3 scheme. The calculated binding energies are very similar for adsorption with the nitrogen or the oxygen end towards the surface, whilst calculated vibrational frequencies of adsorbed N2O match the experimental values better when assuming an O-down adsorption structure.