DFT determination of ammonia adsorption configurations on the Pt{1 0 0}-(1 × 1) surface at low coverage

► Two stable ammonia states on the Pt{1 0 0}-(1 × 1) surface at low coverage. ► α-NH3 bound to one Pt atom and β-NH3 H-bond to α-NH3. ► Constant repulsive interaction energy among adsorbates (ammonia monomers or dimers). ► Saturation coverage for α-NH3 is estimated to be 0.29 ML.