The Adsorption of Atomic Nitrogen on Ru(0001): Geometry and Energetics

TL;DR

This study investigates the atomic-level geometry and energetics of nitrogen adsorption on Ru(0001) surfaces, revealing deep nitrogen sinking into the surface and strong Ru-N bonds through experimental and computational methods.

Contribution

It provides detailed adsorption geometries and energetics of nitrogen on Ru(0001), combining LEED analysis with ab-initio calculations for the first time.

Findings

Nitrogen occupies threefold hcp sites on Ru(0001).

Nitrogen sinks deeply into the top Ru layer.

Strong Ru-N bonds with binding energies around 5.6-5.8 eV.

Abstract

The local adsorption geometries of the (2x2)-N and the (sqrt(3)x sqrt(3))R30^o -N phases on the Ru(0001) surface are determined by analyzing low-energy electron diffraction (LEED) intensity data. For both phases, nitrogen occupies the threefold hcp site. The nitrogen sinks deeply into the top Ru layer resulting in a N-Ru interlayer distance of 1.05 AA and 1.10 AA in the (2x2) and the (sqrt(3)x sqrt(3))R30^o unit cell, respectively. This result is attributed to a strong N binding to the Ru surface (Ru--N bond length = 1.93 AA) in both phases as also evidenced by ab-initio calculations which revealed binding energies of 5.82 eV and 5.59 eV, respectively.