The Structure of the Chiral Pt{531} Surface:  A Combined LEED and DFT Study

Abstract

The structure of the chiral kinked Pt531 surface has been determined by low-energy electron diffraction intensity-versus-energy (LEED-IV) analysis and density functional theory (DFT). Large contractions and expansions of the vertical interlayer distances with respect to the bulk-terminated surface geometry were found for the first six layers (LEED: d12 = 0.44 A, d23 = 0.69 A, d34 = 0.49 A, d45 = 0.95 A, d56 = 0.56 A; DFT: d12 = 0.51 A, d23 = 0.55 A, d34 = 0.74 A, d45 = 0.78 A, d56 = 0.63 A; dbulk = 0.66 A). Energy-dependent cancellations of LEED spots over unusually large energy ranges, up to 100 eV, can be explained by surface roughness and reproduced by applying a model involving 0.25 ML of vacancies and adatoms in the scattering calculations. The agreement between the results from LEED and DFT is not as good as in other cases, which could be due to this roughness of the real surface.

Chirality in Amino Acid Overlayers on Cu Surfaces

“…In a quantitative LEED study of clean Pt{531}, many of the diffracted beams were found to exhibit negligible intensity over unusually large energy ranges. Held et al developed a kinematical scattering model to account for these extinctions in terms of atomic roughness [65,66]. On Cu{531}, we observed possible indications of a similar effect in LEED data recorded at room temperature; however, the fits obtained through the kinematical approach were dependent on too many adjustable parameters to be able to draw firm conclusions [64].…”

The Study of Chiral Adsorption Systems Using Synchrotron-Based Structural and Spectroscopic Techniques: Stereospecific Adsorption of Serine on Au-Modified Chiral Cu{531} Surfaces

“…The structures of several unreconstructed clean surfaces have been determined over the last few years by LEED-IV and density functional theory (DFT) with good agreement between experiment and theory [29][30][31]. So far, complete experimental structure determinations (adsorbate conformation and registry with underlying substrate) have not been carried out for chiral molecules adsorbed on intrinsically chiral surfaces.…”

The Chemistry of Intrinsically Chiral Surfaces

“…Such behaviour has been predicted for vicinal surfaces using effective medium theory [24], it has, however, not been observed experimentally for the clean surfaces. Low energy electron diffraction (LEED)-IV analysis and newer DFT studies only find significant inwards relaxations of the low-coordinated surface atoms leaving the symmetry of the surface unchanged [25][26][27][28]. The lateral arrangement of atoms can be significantly disturbed by thermally induced disorder [29, 30] but, according to Monte-Carlo simulations by Sholl and co-workers [31,32], this leaves the overall chirality of the surface unchanged.…”