SELECTIVE LASER SPECTROSCOPY OF MOLECULAR IONS $UO_{2}{^{2+}}$ ADSORBED ON DISPERSE $SiO_{2}$ SURFACE

1. Glinka Yu D., Degoda V. Ya, Krak T.B. et all. $//$ J. Appl. Spectr. 1993, 59, No 3-4. 286-292Author Institution: Institute of Surface Chemistry of the Ukrainian Academy of Sciences; Department of Physics, Kiev State UniversityLow-temperature luminescence spectra of molecular ions $UO_{2}{^{2+}}$ adsorbed on disperse $SiO_{2}$ surface investigated under selective laser excitation. It was determined that molecular ions are very sensitive luminescent probes for investigations of active in adsorption centers (AC) on disperse silicon dioxide surface. Different AC causes many elementary luminescene spectra. It was established urnayl ions link with the surface by means of water molecules. $H_{2}O$-molecules coordinate uranium in water-uranyl completes and take part in the formation of absorption bonds. One can observe two AC types corresponding to physical and chemical adsorption states [1]. To our mind, the first type complexes are fixed on surface hydroxyls by hydrogen bonds. The chemosorbed complexes are formed under interaction of water molecules in water-uranyl complexes with surface silicon, bridging Oxygen atoms, and surface structural defects. It is established that $UO_{2}{^{2+}}$ ions are fixed on the surface by means of two or three water molecules forming water-uranyl completes. Active in absorption centers for these complexes are surface sylanol groups