As is well known, small metal particles (SMP) are the main morphological element of different nanomaterials. The present work is devoted to research of electronic and defective structure of metal nanomaterials by methods of an electron - positron annihilation (EPA).
1. Applied metallical catalysts with the size of active metal (Pt, Pd, Ir, Ni) about 1-10nm, deposited on inner surface of high-porous oxids (Al2O3) with specific surface ~500m2/g.
2. Powders of a tungsten and molybdenum with a characteristic grain size~ 1-100 nm, obtained both ordinary hydrometallurgical way (d~100nm), and method of plasma sputtering(d~10nm).
Electronic spectrum and energy levels of SMP are computed . The existence of quantum size effects in spectra of an electron - positron annihilation on SMP is showed. The conditions of quantum size effects appearing in spectra of EPA are determined. As a result the following outcomes are obtained:
1. The direct correlation of EPA parameters with degree of dispersion of active metal Ir in catalyst is detected. It is showed, that on an initial stage the active metal on a surface of the carrier has structure of a charged metlical cluster.
2. In ultra dispersed metal powders W and Mo (1-10 nm) the volumetric and surface positron and electronic bound states are investigated. The electronic wave functions of a positron and adding electron in similar SMP structures are determined from experimental spectra of electron-positron annihilation . The existence of size quantum effects in electron-positron annihilation spectra of ultra dispersed metal powders is showed. The conditions of appearance of quantum size effects and the wave functions and energy levels of quantum levels in low dimensional structures are determined.
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