Spectroscopic studies on the mixed Nd3+-La3+ and Ho3+-Gd3+ acetate systems as an example of the determination of stability constants from electronic spectroscopic data

Abstract The previously worked out spectroscopic method of determination of stability constants of lanthanide ions displaying hypersensitive transitions in absorption spectra [ions of f 2 – f 6 and f 8 – f 12 configurations] has been extended to all the lanthanide ions. The method is based upon measurements of the oscillator strength of hypersensitive transitions of mixed systems of equimolar concentrations containing two different lanthanide ions, in the spectrum one of which a hypersensitive transition is easily observed. The method was proved on the La 3+ -acetate and Gd 3+ -acetate systems, both the lanthanide ions having no hypersensitive transitions within the generally available UV and VIS measurement range.