Short description of important scientific result: The nuclear pseudoquadrupole resonance was observed for the first time in Van-Vleck paramagnet PrF3. It was found that crystal electric field parameters of nanocrystals differ from those in single crystals. Co-authors: A.S.Aleksandrov, M.S.Tagirov, E.M. Alakshin, A.V.Klochkov, S.L.Korableva.