Chirality at surfaces has become a strong focus within the surface science community. A particular motivation is the prospect of using heterogeneous catalysis over chiral solid surfaces for asymmetric synthesis, a prospect which has clear relevance to the pharmaceutical industry. Small amino acids adsorbed on Cu surfaces have emerged as important model systems for studying the interaction of chiral molecules with metal surfaces. In this article, we review the current state of knowledge of these systems, and present the results of new experimental studies of alanine overlayers on Cu{311} and {531} surfaces. Our work on Cu{311} helps us to understand the interplay between different manifestations of chirality, especially ''footprint chirality'', in the overlayers. Cu{531} is an intrinsically chiral surface orientation; our data reveal strongly enantiospecific alanine-induced restructuring of this surface. This points the way towards a promising route for obtaining strongly enantiospecific interactions with chiral adsorbates.

We have used synchrotron-based high-resolution X-ray photoelectron spectroscopy in combination with ab initio density functional theory calculations to investigate the characteristics of water and CO adsorption on the bimetallic Cu/Pt{110}-(2 × 1) surface at a Cu coverage near 0.5 ML. Cu fills the troughs of the reconstructed clean surface forming nanowires, which are stable up to 830 K. Their presence dramatically influences the adsorption of water and CO. Water adsorption changes from intact to partially dissociated while the desorption temperature of CO on this surface increases by up to 27 K with respect to the clean Pt{110} surface. Ab initio calculations and experimental valence band spectra reveal that the Cu 3d-band is narrowed and shifted upward with respect to bulk Cu surfaces. This and electron donation to surface Pt atoms cause the increase in the bond strength between CO and the Pt surface atoms. The pathway for water dissociation occurs via Cu surface atoms. The heat of adsorption of water bonding to Cu surface atoms was calculated to be 0.82 eV, which is significantly higher than on the clean Pt{110} surface; the activation energy for partial dissociation is 0.53 eV (not corrected for zero point energy).

The adsorption of carbon monoxide on the Pt{110} surface at coverages of 0.5 ML and 1.0 ML was investigated using quantitative low-energy electron diffraction (LEED IV) and density-functional theory (DFT). At 0.5 ML CO lifts the reconstruction of the clean surface but does not form an ordered overlayer. At the saturation coverage, 1.0 ML, a wellordered p(2 × 1) superstructure with glide line symmetry is formed. It was confirmed that the CO molecules adsorb on top of the Pt atoms in the top-most substrate layer with the molecular axes tilted by ±22 • with respect to the surface normal in alternating directions away from the close packed rows of Pt atoms. This is accompanied by significant lateral shifts of 0.55Å away from the atop sites in the same direction as the tilt. The top-most substrate layer relaxes inwards by -4 % with respect to the bulk-terminated atom positions, while the consecutive layers only show minor relaxations. Despite the lack of long-range order in the 0.5 ML CO layer it was possible to determine key structural parameters by LEED IV using only the intensities of the integer-order spots. At this coverage CO also adsorbs on atop sites with the molecular axis closer to the surface normal (< 10 • ). The average substrate relaxations in each layer are similar for both coverages and consistent with DFT calculations performed for a variety of ordered structures with coverages of 1.0 ML and 0.5 ML.