Experimental and theoretical studies of the electronic spectra of mixed framework phosphates of Zr and Coстатья
Статья опубликована в высокорейтинговом журнале
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
Аннотация:Electronic diffuse reflectance spectra were acquired for samples of mixed framework phosphates of zirconium and cobalt calcined in a broad temperature range (40-900°C). Analysis of the spectral features and their comparison with data available for different cobalt phosphates and CoAPO revealed that in complex framework phosphates the nearest coordination sphere of Co cations corresponds mainly to the oxygen polyhedra with a low coordination number such as the tetrahedron, pyramid, etc. In the frames of the time-dependent DFT method (TDDFT), the electronic excitation energies for cobalt cations in different oxygen environments have been calculated. The results obtained allowed us to describe the spectra of mixed cobalt-zirconium phosphates of various crystallinity both in the d-d transition and charge-transfer ranges with due regard for the simultaneous presence of Co cations in different coordination polyhedra and spin states. In prediction of the spectral features, the approach used in this work was shown to reasonably agree with the traditional concepts and experience in analysis of the electronic spectra of transition metal cations in their complexes and inorganic frameworks.