Morphology and CO adsorptive properties of CuCl polycrystalline films: a SEM and FTIR study

The morphology of the CuCl film microcrystals was determined by means of SEM analysis. By comparing the micrographs with the computer graphic modelling results, polyhedra reproducing the particle shape were obtained, which are characterized by the predominant presence of (110) faces. The surface properties of these model solids have been studied, by means of FTIR spectroscopy of adsorbed CO. The remarkably small half-width (Delta (v) over bar = 5.2 cm(-1)) of the stretching band of CO adsorbed on (110) faces of the microcrystals of the most severely sintered films is indicative of high surface regularity, The frequency of the (v) over bar(CO) (2134 cm(-1)), lower than that of CO gas phase, and the increased value of the vibrational polarizability (alpha(v) = 0.13 Angstrom(3)) indicate that in the CO/CuCl interaction, besides predominant Stark and sigma contributions, d-pi overlap effects are also weakly contributing.