LEED crystallographic investigations of two surface structures designated Zr(0001)-(1 × 1)-C

Abstract

Multiple scattering analyses of LEED intensities have been made for two Zr(0001)-(1 × 1)-C surfaces corresponding to a low and a high coverage of C. For the first, a moderate level of correspondence between experimental and calculated I( E) curves is reached when the C atoms occupy octahedral holes between the first and second metal layers to give a ZrC bond distance of 2.29 Å. In this case the absorbed C causes only a 3.5% increase in the neighbouring ZrZr interlayer spacing. However, the normal incidence study for the high-coverage surface suggests that this spacing is then increased by about 25% over the bulk value; such an expansion is consistent with C incorporation into tetrahedral hole underlayer sites.