Nanocomposites and nanomaterials

Positronics in contemporary nanocomposites science and engineering:  the case of PVP-capped glassy arsenoselenides
Shpotyuk Yaroslav1,2, B. Mahlovanyi1,2*, Ingram Adam3, Shpotyuk Oleh4,5, Filipecki Jacek4
1 Institute of Physics, University of Rzeszow, 35-959 Rzeszow, Poland
2 Ivan Franko National University of Lviv, 79017 Lviv, Ukraine
E-mail: yashpotyuk@gmail.com
3 Opole University of Technology,  45370 Opole, Poland
4Jan Dlugosz University in Czestochowa, 42201 Czestochowa, Poland
5 O.G. Vlokh Institute of Physical Optics, 79005 Lviv, Ukraine

Possibilities of positron annihilation lifetime (PAL) spectroscopy applied to characterize nanosization processes in nanocomposites are analyzed in details. The fundamentals of PAL spectroscopy applied to inhomogeneous nanoparticle-embedded substances are discussed. 
The algorithm to treat PAL data for such substances within three-state mixed trapping model evolving competitive channels of positron and positroniun Ps (bound electron-positron state) annihilation referred to as the x3-x2-CDA (coupling decomposition algorithm) [1,2] is given. Under high-energy wet milling, the inter-nanoparticle Ps-decaying sites in preferential PVP environment are shown to replace free-volume positron traps in dry-milled pellets with defect-specific positron lifetime corresponding to di-/tri-atomic vacancies in glassy g-As-Se matrix.  

1.	Shpotyuk O., Filipecki J., Ingram A., Golovchak R., Vakiv M., Klym H., Balitska V., Shpotyuk M., Kozdras A. Positronics of subnanometer atomistic imperfections in solids as a high-informative structure characterization tool // Nanoscale Res Lett.-2015.-10.-P. 77-1-5.
2.	Shpotyuk O., Ingram A., Shpotyuk Y. Free-volume characterization of nanostructurized substances by positron annihilation lifetime spectroscopy // Nucl Instr Meth Phys Res. B.-2018.-416.-P. 102-109.