Methodological possibilities of positron annihilation lifetime (PAL) spectroscopy applied to characterize different types of nanomaterials treated within three-term fitting procedure are critically reconsidered. In contrast to conventional three-term analysis based on admixed positron- and positronium-trapping modes, the process of nanostructurization is considered as substitutional positron-positronium trapping within the same host matrix. Developed formalism allows estimate interfacial void volumes responsible for positron trapping and characteristic bulk positron lifetimes in nanoparticle-affected inhomogeneous media. This algorithm was well justified at the example of thermally induced nanostructurization occurring in 80GeSe2-20Ga2Se3 glass.

It is shown that positron annihilation lifetime spectroscopy is a quite promising tool for nanostructural characterisation of humidity-sensitive spinel-type MgAl ₂ O ₄ ceramics, the results being achieved provided four-component fitting procedure with arbitrary lifetimes is applied to treat mathematically the measured spectra. It is shown that Tao-Eldrup model is adequate for calculation of nanopore size in MgAl ₂ O ₄ ceramics using lifetime values of the third and four components.