CHEMISORPTION ON COMPOSITE SYSTEMS

The chemisorption energy of hydrogen on composite systems, such as Cu/NixCu1-x and ZnO/NixCu1-x, is investigated using the complex-energy-plane integration approach. The electronic properties of the composite substrate are described by using the Green function method within the framework of the tight-binding approximation. The coherent-potential approximation is used to cope with the alloys. The results are as follows. (1) The Cu (or ZnO) film which grows on the Ni or NixCu1-x substrates can weaken (or strengthen) the chemisorption of H. (2) The chemisorption properties can be modified by the alloy concentration. (3) A Cu (or ZnO) film of ten layers thickness can be taken as bulk Cu (or ZnO).