A new interpretation of the √7×√7 R19.1° structure for P adsorbed on a Ni(111) surface

Barrow, Elizabeth; Seuser, Grant S.; Ariga-Miwa, Hiroko; Chen, Donna; Lauterbach, Jochen A.; Asakura, Kiyotaka

doi:10.1080/14686996.2019.1598239

Cited by 1 publication

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References 70 publications

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“…Small adsorbates like Ar and CO on metals, i.e., for adsorbates with simple point/axial symmetry, have been reported to assume a R 19.1° reconstruction with a smaller than the presently observed unit cell. 75 − 77 Note that Baddeley and Richardson 78 explain two possible causes of chirality in surface reconstructions: (i) symmetry reduction due to the intermolecular bonding pattern (as discussed above) and (ii) the mathematical fact that hexagonal point lattices on hexagonal substrates can form two chiral domains if their rotation is not in sync with the 120° symmetry of the substrate. The R 19.1° superstructure provides such a case.…”

Section: Resultsmentioning

confidence: 99%

Self-Assembly of N-Rich Triimidazoles on Ag(111): Mixing the Pleasures and Pains of Epitaxy and Strain

Ahsan,

Wang,

et al. 2023

J. Phys. Chem. C

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In the present report, homochiral hydrogen-bonded assemblies of heavily Ndoped (C 9 H 6 N 6 ) heterocyclic triimidazole (TT) molecules on an Ag(111) substrate were investigated using scanning tunneling microscopy (STM) and low energy electron diffraction (LEED) techniques. The planar and prochiral TT molecules, which exhibit a threefold rotation symmetry and lack mirror symmetry when assembled on the substrate, carry multiple hydrogen-bonding donor and acceptor functionalities, inevitably leading to the formation of hexameric two-dimensionally extended assemblies that can be either homo-(RR/SS) or heterochiral (RS). Experimental STM data showing well-ordered homochiral domains and experimental LEED data are consistent with simulations assuming the 21 21 × R19.1°o verlayer on the Ag(111) lattice. Importantly, we report the unexpected coincidence of spontaneous resolution with the condensation of neighboring islands in adjacent "Janus pairs". The islands are connected by a characteristic fault zone, an observation that we discuss in the context of the fairly symmetric molecule and its propensity to compromise and benefit from interisland bonding at the expense of lattice mismatches and strain in the defect zone. We relate this to the close to triangular shape and the substantial but weak bonding scheme beyond van der Waals (vdW) of the TT molecules, which is due to the three Ncontaining five-membered imidazole rings. Density functional theory (DFT) calculations show clear energetic differences between homochiral and heterochiral pairwise interactions, clearly supporting the experimental results.

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