Luminescence of europium trifluoroacetates

Communication: Linking the dielectric Debye process in mono-alcohols to density fluctuations

“…Dilution studies [19][20][21][22] and studies of structural isomers [23,24] show that these characteristics may be less distinct, when the Debye process is not well-separated from the alpha process.The notion that this intense dielectric signal originates from linear hydrogen-bonded structures appeared quite early [12,[25][26][27], and observations of a pre-peak in the static structure factor [28] supports this idea by identifying structures on a length scale exceeding the molecular. The different intensities of the Debye process in differ-ent mono-alcohols can be rationalized in terms of these structures being primarily chain-like -leading to a large end-to-end dipole moment -or ring-like -resulting in a (partial) cancellation of the individual dipole moments [12].A number of mechanisms have been suggested to account for the slow dynamics of the Debye process: breaking of hydrogenbonds in a chain and formation of new chains leading to end-to-end fluctuations of the dipole moment [29][30][31], dipole inversion by rotation of the OHgroups [32], and the transient chain model advocated by Gainaru [33], where molecules break off from or add to the ends of the chain which promotes a slow rotation of the effective dipole moment of the chain. A fundamental and predictive model for the elusive Debye process is however still lacking.…”

“…A number of mechanisms have been suggested to account for the slow dynamics of the Debye process: breaking of hydrogenbonds in a chain and formation of new chains leading to end-to-end fluctuations of the dipole moment [29][30][31], dipole inversion by rotation of the OHgroups [32], and the transient chain model advocated by Gainaru [33], where molecules break off from or add to the ends of the chain which promotes a slow rotation of the effective dipole moment of the chain. A fundamental and predictive model for the elusive Debye process is however still lacking.…”

Luminescent properties of europium carboxylates

“…As it may be seen, all the compounds may be divided into two groups. In the spectra of the first group compounds, the bands corresponding to the 5 D 0 e 7 F 2 electro-dipole transition are the most intensive that is typical for most of the luminescent Eu compounds [23,24]. Compounds [Eu(C 8 H 7 O 2 ) 3 $xD$nH 2 O] m and Eu(C 9 H 7 O 2 ) 3 $xD$nH 2 O has such spectra ( Fig.…”

“…The mixed-ligand europium(III) compound with b-diketones were studied by the luminescent and X-ray spectroscopy methods [11,12] white the rare-earth compounds with carboxylic acids were not practically investigated [13,14].…”