Nitrogen Adsorption and Dissociation on Fe(111)

Alkali Promotion ofN2Dissociation over Ru(0001)

“…1. For such small dipole moments, another effect, which we ascribe to a Pauli repulsion, dominates [22]. We note that, for molecular adsorbates with a larger dipole moment, the electrostatics still dominates.…”

“…We note that, for molecular adsorbates with a larger dipole moment, the electrostatics still dominates. For CO adsorbed on Ru(0001), we calculate a much larger dipole moment of 20.11 eÅ, and here the electrostatic interaction also describes the interaction with Na very well [22].…”

“…We use the maximum field outside the surface as a measure of § rather than attempting to find the local field at the height of the adsorbate. For the present purposes, this can be taken as an empirical choice, but a more detailed analysis of the electrostatic interaction between adsorbates shows that the screening of the field in the adsorbate region should not be included, and the field just outside the surface is a reasonable measure of the nonscreened field [10,22].…”

Role of Steps inN2Activation on Ru(0001)

“…The use of the non-self-consistent electron densities introduces a negligible error due to the variational principle [15]. The same method gives an excellent description of N 2 adsorption and dissociation on Fe(111) [16]. The Ru(0001) surface is modeled by a three layer slab repeated periodically with a ͑2 3 2͒, ͑2 3 3͒, or ͑2 3 4͒ unit cell parallel to the surface.…”

Ammonia synthesis at low temperatures

“…[5][6][7][8][9][10][11][12][13][14][15][16][17] The reaction proceeds via dissociation of N 2 and H 2 on the surface with subsequent hydrogenation of the adsorbed N atoms. Our density functional theory ͑DFT͒ calculations of the reaction energetics on Ru surfaces illustrate the reaction mechanism, see Fig.…”