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Direct experimental evidence for substrate adatom incorporation into a molecular overlayer

DOI: 10.1021/acs.jpcc.2c01432 DOI Help

Authors: Philip J. Mousley (Diamond Light Source) , Luke A. Rochford (University of Birmingham) , Paul T. P. Ryan (Diamond Light Source; Imperial College London) , Philip Blowey (Diamond Light Source, University of Warwick) , James Lawrence (University of Warwick) , David A. Duncan (Diamond Light Source) , Hadeel Hussain (Diamond Light Source) , Billal Sohail (University of Warwick) , Tien-Lin Lee (Diamond Light Source) , Gavin R. Bell (University of Warwick) , Giovanni Costantini (University of Warwick) , Reinhard J. Maurer (University of Warwick) , Christopher Nicklin (Diamond Light Source) , D. Phil Woodruff (University of Warwick)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: The Journal Of Physical Chemistry C

State: Published (Approved)
Published: April 2022
Diamond Proposal Number(s): 14884 , 4884

Open Access Open Access

Abstract: While the phenomenon of metal substrate adatom incorporation into molecular overlayers is generally believed to occur in several systems, the experimental evidence for this relies on the interpretation of scanning tunneling microscopy (STM) images, which can be ambiguous and provides no quantitative structural information. We show that surface X-ray diffraction (SXRD) uniquely provides unambiguous identification of these metal adatoms. We present the results of a detailed structural study of the Au(111)-F4TCNQ system, combining surface characterization by STM, low-energy electron diffraction, and soft X-ray photoelectron spectroscopy with quantitative experimental structural information from normal incidence X-ray standing wave (NIXSW) and SXRD, together with dispersion-corrected density functional theory (DFT) calculations. Excellent agreement is found between the NIXSW data and the DFT calculations regarding the height and conformation of the adsorbed molecule, which has a twisted geometry rather than the previously supposed inverted bowl shape. SXRD measurements provide unequivocal evidence for the presence and location of Au adatoms, while the DFT calculations show this reconstruction to be strongly energetically favored.

Journal Keywords: DFT calculations; Adsorption; Gold; Molecules; Layers

Subject Areas: Chemistry, Physics

Instruments: I07-Surface & interface diffraction , I09-Surface and Interface Structural Analysis

Added On: 21/04/2022 14:53


Discipline Tags:

Surfaces Physics Physical Chemistry Chemistry

Technical Tags:

Diffraction Spectroscopy X-ray Standing Wave (XSW) X-ray Photoelectron Spectroscopy (XPS)