Additive colouring of CaF2:Yb crystals: determination of Yb2+ concentration in CaF2:Yb crystals and ceramics

Radiation-Stimulated Transformations Yb-=SUP=-3+-=/SUP=-->Yb-=SUP=-2+-=/SUP=- and Yb-=SUP=-3+-=/SUP=-->Yb-=SUP=-3+-=/SUP=- in Single Crystals and Nanoceramics CaF-=SUB=-2-=/SUB=- : YbF-=SUB=-3-=/SUB=-

“…The intensities of the observed absorption bands in a range of 214−360 nm for crystalline and ceramic samples correspond to electronic transitions from the 1 S 0 ( 4 f 14 ) to the 4 f 14 5d levels of the Yb 2+ ions, and in the range of 920−1060 nmto the 2 F 7/2 − 2 F 5/2 transitions of the Yb 3+ ions [20,31]. Since f−d transitions are allowed, in contrast to f−f transitions, the intensities of the corresponding absorption bands differ by about a factor of 10 4 [32].…”

Comment on “The Complexity of the CaF2:Yb System: A Huge, Reversible, X-ray-Induced Valence Reduction”

“…Development of this technique was based on conversion of all Yb­(III) ions in the standard sample to Yb­(II) by reduction with calcium metal vapor. Experiments by Shcheulin et al unequivocally proved that cross-section values for Yb­(II) f → d permitted transitions were about 10,000 times higher than the values of Yb­(III) f → f forbidden transitions (technique accuracy is about 0.0014 × 10 18 cm –3 ). The technique of Shcheulin et al is simple and available for everyone utilizing polished monocrystalline or optical ceramics plates.…”

“…Experiments by Shcheulin et al unequivocally proved that cross-section values for Yb­(II) f → d permitted transitions were about 10,000 times higher than the values of Yb­(III) f → f forbidden transitions (technique accuracy is about 0.0014 × 10 18 cm –3 ). The technique of Shcheulin et al is simple and available for everyone utilizing polished monocrystalline or optical ceramics plates. The lack of reference to the Shcheulin et al method in the MacKeen et al paper is surprising.…”

“…The technique of Shcheulin et al is simple and available for everyone utilizing polished monocrystalline or optical ceramics plates. The lack of reference to the Shcheulin et al method in the MacKeen et al paper is surprising.…”

“…The authors mention that their study became possible only after they developed their protocol to determine Yb­(II) concentration in CaF 2 :Yb crystals in the background of Yb­(III) ions. , However, said method has been known since earlier times, when Shcheulin et al published their technique of calculating Yb­(II) concentration by determining cross sections of Yb­(II) absorption bands in CaF 2 :Yb matrices. Development of this technique was based on conversion of all Yb­(III) ions in the standard sample to Yb­(II) by reduction with calcium metal vapor.…”