The luminescence properties of double molybdates can be changed by modifying their crystal structure through stoichiometric variations while preserving elemental composition. In this study, the structural and luminescent characteristics of K5Nd(MoO4)4 (K5Nd) and KNd5(MoO4)8 (KNd5) are investigated. Powder X-ray diffraction analysis revealed that K5Nd can be described by either a trigonal or monoclinic crystal system, in which Nd3+ (and K+) ions are located in O6 octahedra, while KNd5 adopts an incommensurately modulated structure, where Nd3+ (K+) ions occupy O8 polyhedral sites. The structural differences lead to significant variations in luminescence properties. Notable differences were observed in the line structure and decay time of the emission resulting from the 4F3/2 - 4I9/2 transition, which were explained by differences in site symmetry and in non-radiative energy transfer for Nd3+ in different crystal structures. The influence of partial reabsorption on the structure of these emission lines is shown, which depends on the absorption coefficient defining the penetration depth of the exciting photons. The energy of exciton creation and the process of energy transfer from the separated electrons and holes to Nd3+ emission centers were analyzed using excitation spectra measured in a broad energy region using synchrotron radiation. The contribution of the electronic states of the atoms composing the studied molybdates to the formation of energy bands is discussed.
}}, author = {{Jamal, Muhammad Usama and Nagirnyi, Vitali and Mändar, Hugo and Chernenko, Kirill and Spassky, Dmitry}}, issn = {{0022-2313}}, keywords = {{Concentration quenching; Energy transfer; KNd(MoO); Luminescence; Thermal population}}, language = {{eng}}, publisher = {{Elsevier}}, series = {{Journal of Luminescence}}, title = {{Structural and luminescence properties of K5Nd(MoO4)4 and KNd5(MoO4)8}}, url = {{http://dx.doi.org/10.1016/j.jlumin.2026.121995}}, doi = {{10.1016/j.jlumin.2026.121995}}, volume = {{297}}, year = {{2026}}, }