Periodic domain boundary ordering in a dense molecular adlayer: Sub-saturation carbon monoxide on Pd(111)

Journal Article · Sat Dec 31 00:00:00 EST 2016 · Surface Science

DOI:https://doi.org/10.1016/j.susc.2016.12.004· OSTI ID:1409642

Xu, Pan ^[1]; Liu, Shizhong ^[1]; Hong, Sung -Young ^[2]; Liu, Ping ^[2]; White, Michael G. ^[3]; Camillone, III, Nicholas ^[2]

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1. Stony Brook Univ., Stony Brook, NY (United States)
2. Brookhaven National Lab. (BNL), Upton, NY (United States)
3. Stony Brook Univ., Stony Brook, NY (United States); Brookhaven National Lab. (BNL), Upton, NY (United States)

Here, we describe a previously unreported ordered phase of carbon monoxide adsorbed on the (111) facet of single crystal palladium at near-saturation coverage. The adlayer superstructure is identified from low energy electron diffraction to be c(16×2) with respect to the underlying Pd(111) surface net. The ideal coverage is determined to be 0.6875 ML, approximately 92% of the 0.75–ML saturation coverage. Density functional theory calculations support a model for the molecular packing characterized by strips of locally-saturated (2×2) regions, with the CO bound near high-symmetry surface sites, separated by antiphase domain boundaries. The structure exists in a narrow coverage range and is prepared by heating the saturated adlayer to desorb a small fraction of the CO. Comparison of the c(16×2) domain-boundary structure with structural motifs at lower coverages suggests that between 0.6 and 0.6875 ML the adlayer order may be more strongly influenced by interadsorbate repulsion than by adsorption-site-specific interactions. The system is an example of the structural complexity that results from the compromise between adsorbate–substrate and adsorbate–adsorbate interactions.

• Research Organization: Brookhaven National Lab. (BNL), Upton, NY (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: SC0012704
• OSTI ID: 1409642
• Alternate ID(s): OSTI ID: 1397477
• Report Number(s): BNL-114697-2017-JA; R&D Project: CO007; KC0301050
• Journal Information: Surface Science, Vol. 658, Issue C; ISSN 0039-6028
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
Palladium
Carbon monoxide
Low energy electron diffraction (LEED)
Temperature programmed desorption (TPD)
Density functional theory (DFT)
Antiphase domain boundary