THE STUDY ON SYNTHESES AND SOLID-STATE PROPERTIES OF INTERSTITIAL COMPOUNDS BASED ON THE MOLECULAR INTERSPACE ELUCIDATED BY MEANS OF POSITRON ANNIHILATION

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Alkali-metal-saturation-doped fullerides M_6C_<60> (M=K, Rb, Cs) showed three positron lifetime components ; 0.21-0.24, 0.60-0.75, and 3.2-3.7 ns. The 1st component was assigned to arise from the free annihilation of positrons with electrons inside and around C_<60> molecules in the crystals, the 2nd one from the annihilation on the surfaces of the crystals, and the 3rd one from the annihilation through ortho-positronium (o-Ps). Pure C_<60> crystals showed only a single component of 0.427 ns. The substitution of Na^+ in the van der Waals gaps of montmorillonite with Al^<3+>, Zn^<2+>, Pb^<2+>, Cu^<2+>, Mg^<2+> was found to forminorganic interstitial compounds, and that with alkylammoniums to form the monmorillonites of which gaps are filled with long alkyl chains. The h parameters of Doppler-broadening spectra, 0.55-0,58 ; and the 2nd lifetime components, 1.12-1.74 ns, for these montmorillonites are found to have a good correlation with the values observed for their original alkylammonium salt crystals, which demonstrates that the positron annihilation occurs in the region of van der Waals gaps. Further incorporation of oxine into the inorganic interstitial compounds formed metal-oxine-complex-including montmorillonites. Al-oxine and Mg-oxine complexs showed the same fluorescence spectra when they were incorporated into the van der Waals gaps of montmorillonite, but Zn-oxine compex showed fluorescence blue shift of 12 nm when it was inserted into the gaps of montmorillonite. Graphite-potassium intercalation compound, KC_8, was found to generate o-Ps.