title: NO adsorption on Cu(110) and O(2 × 1)/Cu(110) surfaces from density functional theory calculations.
abstract: In a recent study [M. Feng, et al., ACS Nano, 2011, 5, 8877], it was shown that CO molecules adsorbed on the quasi-one-dimensional O(2 × 1)/Cu(110) surface reconstruction tend to form highly-ordered single-molecule-wide rows along the direction perpendicular to the Cu-O chains. This stems from the peculiar tilted adsorption configuration of CO on this substrate, which gives rise to short-range attractive dipole-dipole interactions. Motivated by this observation, here we study the adsorption of nitric oxide (NO) on O(2 × 1)/Cu(110) and Cu(110) using density functional theory, with the aim of elucidating whether a similar behaviour can be expected for this molecule. We first study NO adsorption on a clean Cu(110) surface, where the role of short-range attractions between molecules has already been pointed out by the observation of the formation of NO dimers by scanning tunnelling microscopy [A. Shiotari, et al., Phys. Rev. Lett., 2011, 106, 156104]. On the clean Cu(110), the formation of dimers along the [110̄] direction is favourable, in agreement with published experimental results. However, the formation of extended NO rows is found to be unstable. Regarding the O(2 × 1)/Cu(110) substrate, we observe that NO molecules adsorb in between the Cu-O chains, causing a substantial disruption of the surface structure. Although individual molecules can be tilted with negligible energetic cost along the direction of the Cu-O chains, the interaction among neighbouring molecules was found to be repulsive along all directions and, consequently, the formation of dimers unfavourable.
authors.affiliation: Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, Donostia-San Sebastián E-20018, Spain. swbcasam@sc.ehu.es and Departamento de Física de Materiales UPV/EHU, Apartado 1072, Donostia-San Sebastián E-20018, Spain.
authors.forename: Antón X
authors.initials: AX
authors.lastname: Brión-Ríos
authors.affiliation: Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, Donostia-San Sebastián E-20018, Spain. swbcasam@sc.ehu.es and Centro de Física de Materiales (CFM-MPC) CSIC-UPV/EHU, Paseo Manuel de Lardizabal 5, E-20018, Donostia-San Sebastián, Spain.
authors.forename: Daniel
authors.initials: D
authors.lastname: Sánchez-Portal
authors.affiliation: Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, Donostia-San Sebastián E-20018, Spain. swbcasam@sc.ehu.es and IKERBASQUE, Basque Foundation for Science, Bilbao E-48011, Spain.
authors.forename: Pepa
authors.initials: P
authors.lastname: Cabrera-Sanfelix