Atomic layer epitaxy of copper: an ab initio investigation of the CuCl/H-2process - II. Reaction energies

Reaction energies for different reaction pathways in the CuCl/H-2 process o ccurring in the gas phase as well as on a Cu(111) surface have been calcula ted using Density Functional Theory. All reactions, occurring in the gas ph ase as well as in the solid/vapour interface where gaseous atomic hydrogen was used as reducing agent were highly exothermic with reaction energies be tween approximately -200 and -300 kJ mol(-1). When molecular hydrogen was u sed, the reactions were endothermic. A gas phase reaction had a reaction en ergy of about 100 kJ mol(-1), whereas for reactions between adsorbed CuCl a nd gaseous H-2, this value decreased to between 32 and 64 kJ mol(-1) depend ing on reaction pathway. This was slightly lower than for surface reactions between CuCl and hydrogen where the reaction energies varied between 53 an d 88 kJ mol(-1). (C) 1999 Elsevier Science B.V. All rights reserved.