Intensities of optical transitions in the spectra of Eu3+-doped rare-earth formates

Intensity of cooperative vibronic transitions in the Eu(III), Gd(III) and Tb(III) formates spectra

“…Interpretation of the Stark structure of the europium ion levels has been realized in terms of the semiempirical crystalline field (CF) theory. [ 12,27,28 ] According to the group theory, levels with J = 1 ( 5 D 1 and 7 F 1 ) in the field of a trigonal symmetry are split into two components: E and A 2 . A theoretical value of the ratio of intensities for the transitions 5 D 0 → 7 F 1 (E) and 5 D 0 → 7 F 1 (А 2 ) is equal to 2:1.…”

“…Variants I and II result in a different sign for the B 4 0 parameter. The first variant of assignment appears to be more likely [ 12 ] as the negative sign of B 4 0 is typical for polyhedrons of a similar type in ethylsulphates and chlorides. [ 24 ]…”

“…The calculated values of rate constants of vibronic transitions A v тheor for Ln(HCOО) 3 (Ln = Eu, Tb) and Y 0.95 Eu 0.05 (HCOO) 3 are given in Table 3 along with the experimental values A v exp obtained from the relationship A v exp = (I v /I 0 ) × A 0 , where A 0 are the probabilities of purely electronic transitions. [ 12,13 ]…”

“…The synthesis procedure was analogous to that previously described, [ 23 ] where purity, stoichiometric, and phase composition were controlled by chemical, X‐ray diffraction, and infrared (IR) methods. Formates of the type Ln(HCOO) 3 (Ln = Eu, Tb, Gd) and Y(HCOO) 3 ⋅2H 2 O doped with Eu 3+ and Tb 3+ (C ~1 mol%) were synthesized by means of the interaction of the corresponding lanthanide oxides with solutions of the formic acid at 80°C temperature with constant stirring on a magnetic stirrer.…”

“…It provides an opportunity to measure the vibrational spectra of ligands coordinated to lanthanide ions. [8][9][10][11] The lanthanide formates are self-activated, efficient luminescent crystals, [12,13] and can be viewed as the elementary type in the whole class of the oxygen-containing lanthanide complexes with organic ligands. In last decades narrow band-emitting molecular lanthanide complexes have found wide applications as hybrid white LEDs.…”