LUMINESCENCE, ABSORPTION AND EXCITATION SPECTROSCOPY OF CS5EU(N3)8

Electronic absorption, luminescence and laser excitation spectra of the complex ion Eu(N3)85- in single crystals of Cs5Eu(N3)8 have been measured at temperatures down to 4 K. Although the crystal structure shows the presence of only one type of Eu(N3)85- complex ion, in which nearest N atoms form an approximate D4d (square anti-prismatic) coordination polyhedron about the Eu atom, the spectra clearly show the presence of two distinct, but closely similar, types of Eu atoms. For one of these sites, emission from the 5D0 state to all the expected crystal field states of the F-7(J)(J = 0-6) manifold and from the 5D1 state to all of the F-7(J)(J = 0, 1, 2, 3) states is observed and, together with the absorption and the excitation spectra, permit the location of 56 of the 57 crystal field states expected below 23000 cm-1.