Oxygen adsorption on a ZrC(111) surface: angle-resolved photoemission study

Angle-resolved photoemission spectroscopy utilizing synchrotron radiation h as been used to study the adsorption state of oxygen on a ZrC(III) surface. Oxygen adsorbs dissociatively at room temperature forming a (root 3 x root 3)R30 degrees overlayer at 0.4-0.8 L and a (1 x 1) overlayer for further e xposure. The two-dimensional band structure of the O 2p-derived states is m easured for the (I x I)-O surface in the two symmetry directions; [2 (1) ov er bar (1) over bar] (<(Gamma)over bar>(M) over bar) and [01 (1) over bar] (<(Gamma)over bar>(K) over bar) directions of the ZrC(111) surface. It is f ound that the O 2p(x), 2p(y) and 2p(z)-derived bands are formed at nearly t he same binding energy region, indicating that the O 2p(x), 2p(y) and 2p(z) orbitals should have an almost equal contribution to the chemisorption bon ding on the ZrC(111) surface. (C) 2000 Elsevier Science B.V. All rights res erved.