I-70 Investigation of Structural Vacancies in Titanium Monoxide by Electron-Positron Annihilation / A. A. Valeeva, A. A. Rempel, W. Sprengel, H. -E. Schaefer // Physics of the Solid State. - 2009. - Vol. 51, № 5. - P924-929 : il. - Bibliogr. : p. 928-929 (30 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): МОНООКСИД ТИТАНА -- АННИГИЛЯЦИЯ ЭЛЕКТРОННО-ПОЗИТРОННАЯ -- НЕСТЕХИОМЕТРИЯ Аннотация: Local atomic environment of vacancies in nonstoichiometric titanium monoxide ranging in composition from TiO0.74 to TiO1.26 was studied by electron–positron annihilation. Analysis of the Doppler broadening spectra of the annihilation gamma line for titanium and liquid oxygen showed that positrons in titanium monoxide are trapped by titanium vacancies. Experiments revealed that the lifetime of positrons in ordered and disordered titanium monoxide TiOy increases with increasing oxygen content y and varies from 184 to 210 ps. Data on the valence electron density permitted the prediction that the lifetime of free positrons in stoichiometric titanium monoxide is about 140 ps and the lifetime of positrons localized in an oxygen vacancy is about 170 ps. The method used to analyze the gamma-line Doppler broadening spectra makes it possible to determine the type and number of atoms around a vacancy and to investigate order–disorder phase transformations in nonstoichiometric compounds Полный текст |