Author/Authors :
A. Gutiérrez-Sosa، نويسنده , , A. and Evans، نويسنده , , T.M. and Woodhead، نويسنده , , A.P. and Lindsay، نويسنده , , R. and Muryn، نويسنده , , C.A. and Thornton، نويسنده , , G. and Yoshihara، نويسنده , , J. and Parker، نويسنده , , S.C. and Campbell، نويسنده , , C.T. and Oldman، نويسنده , , R.J.، نويسنده ,
Abstract :
The orientation of formic acid (HCOOH) on ZnO(0 0 0 1̄)–O and the effect of co-adsorbed Cu have been studied using polarisation dependent C K-edge near edge X-ray absorption fine structure. Formate created by exposure of the substrate to 20 L of HCOOH at 110 K and heating to 340 K is tilted by 55±5° with respect to the surface normal. Pre-adsorbing Cu to create 2D islands covering about half the substrate results in an apparent tilt angle of 32±5° with respect to the surface normal. Since this is close to the magic angle, the apparent tilt could arise from a random orientation of the molecule. The origin of the apparent tilt is likely to be buckling of the Cu(1 1 0)-like islands.
Keywords :
Near edge extended X-ray absorption fine structure (NEXAFS) , Chemisorption , Copper , Zinc oxide , Carboxylic acid , Low index single crystal surfaces
