On the relation between of intensity of ''supersensitive'' transitions of lanthanide ion adsorption spectra in solutions of complexes with parameter U(2) of the Judd-Ofelt theory

The absorption bands of neodymium, holmium and erbium ions in the visible spectrum and the absorption band of thulium with a maximum at 12.700 cm-1 have been chosen to investigate the relationship between the parameter U(2) and the value of the oscillator force in solutions of complexes with a substantial manifestation of the ligand field. It was shown that the values of the parameter U(2) increase in the order Tm3+<Er3+<Nd3+<Ho3+ from 0.24 to 1.52. For the investigated lanthanide ions, the oscillator force absorption bands, corresponding to the super-sensitive jumps, are proportional on a strong manifestation of the effect of the ligand field, to the parameter U(2) of the Judd-Ofelt theory in the power of 1.5 to 1.65