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A structural investigation of the interaction of oxalic acid with Cu(110)

DOI: 10.1016/j.susc.2017.10.025 DOI Help

Authors: T. W. White (University of Warwick) , D. A. Duncan (Technische Universität München; Diamond Light Source) , S. Fortuna (SISSA) , Y.-l. Wang (Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences) , B. Moreton (University of Warwick) , T.-l. Lee (Diamond Light Source) , Philip Blowey (University of Warwick) , G. Costantini (University of Warwick) , D. P. Woodruff (University of Warwick)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Surface Science

State: Published (Approved)
Published: October 2017
Diamond Proposal Number(s): 8436

Abstract: The interaction of oxalic acid with the Cu(110) surface has been investigated by a combination of scanning tunnelling microscopy (STM), low energy electron diffraction (LEED), soft X-ray photoelectron spectroscopy (SXPS), near-edge X-ray absorption fine structure (NEXAFS) and scanned-energy mode photoelectron diffraction (PhD), and density functional theory (DFT). O 1s SXPS and O K-edge NEXAFS show that at high coverages a singly deprotonated monooxalate is formed with its molecular plane perpendicular to the surface and lying in the [11¯0] azimuth, while at low coverage a doubly-deprotonated dioxalate is formed with its molecular plane parallel to the surface. STM, LEED and SXPS show the dioxalate to form a (3 × 2) ordered phase with a coverage of 1/6 ML. O 1s PhD modulation spectra for the monooxalate phase are found to be simulated by a geometry in which the carboxylate O atoms occupy near-atop sites on nearest-neighbour surface Cu atoms in [11¯0] rows, with a Cu-O bondlength of 2.00±0.04 Å. STM images of the (3 × 2) phase show some centred molecules attributed to adsorption on second-layer Cu atoms below missing [001] rows of surface Cu atoms, while DFT calculations show adsorption on a (3 × 2) missing row surface (with every third [001] Cu surface row removed) is favoured over adsorption on the unreconstructed surface. O 1s PhD data from dioxalate is best fitted by a structure similar to that found by DFT to have the lowest energy, although there are some significant differences in intramolecular bondlengths.

Subject Areas: Chemistry


Instruments: I09-Surface and Interface Structural Analysis