Binding energy of a parapositronium in nanovoids of metals

The theoretical studies of the binding energy of a parapositronium in a nanovoid in a nanocrystalline metal as a function of the nanovoid radius are carried out. A new optical spectroscopy method based on the comparison of experimental absorption (and radiation) spectra of a positronium with the results of theoretical calculations is proposed for the determination of the parapositronium structure.