A PHOTOELECTRON DIFFRACTION STUDY OF CU(110)-(2X1)-O

The adsorption of atomic oxygen on Cu{110} has been studied using scanned energy mode photoelectron diffraction from the O 1s level in the range 80-400 eV. Experiments were carried out for normal emission as well as for emission angles of 39°, 57° and 67° in the <110> azimuth. We find that the oxygen is adsorbed in the long bridge site at a distance of 1.98 Å from copper atoms in the second layer. This is consistent with oxygen lying 0.23 Å above the surface with a Cu-O bond length of 1.82 Å, if the spacing between the top two copper layers is identical to that of the bulk. We cannot, however, rule out the possibility of subsurface oxygen, were there a substantial relaxation of the spacing between the first and second layers of copper atoms. The use of R-factors to compare experimental data and calculated diffraction curves is evaluated. We conclude that both the Zanazzi-Jona and Pendry R-factors may be successfully employed to determine the best agreement between calculation and experimental data. © 1990 Elsevier Science Publishers B.V. (North-Holland).