The local atomic structure of Cu(111): An extended energy loss fine structure investigation

Extended energy loss fine structures spectra (EELFS) above the M-2,M-3 ionisation edge of a Cu(111) single crystal have been obtained at primary electron energies of 1500 and 560 eV, corresponding to a studied layer depth of similar to 15 and similar to 8 Angstrom. For experimental EELFS spectra the solution of an inverse problem has been performed and pair correlation functions (PCFs) have been obtained by Tikhonov's regularisation method with allowance made for normalisation of the atomic intensity of ionisation losses. Parameters of the nearest atomic environment, namely, the bond length, the co-ordination number, the Debye-Waller factor and the parameter of asymmetry of the first peak of the pair correlation function, have been determined for both large (similar to 15 Angstrom) and small (similar to 8 Angstrom) depths of the studied layer. (C) 1998 Elsevier Science B.V. All rights reserved.