Study of the spectral characteristics of surface films of CaF2 and BaF2 crystals doped with Eu, Ce, Sm, and Tm by spectroscopic methods

Брюквина Л.И., Пидгурский С.Н., Ермолаева Е.А., Суворова Л.Ф. Исследование спектральных характеристик поверхностных пленок кристаллов CaF2 и BaF2, активированных Eu, Ce, Sm, Tm, спектроскопическими методами // Оптический журнал. 2007. Т. 74. № 6. С. 65–69.

Bryukvina L.I., Pidgurskiy S.N., Ermolaeva E.A., Suvorova L.F. Study of the spectral characteristics of surface films of CaF2 and BaF2 crystals doped with Eu, Ce, Sm, and Tm by spectroscopic methods [in Russian] // Opticheskii Zhurnal. 2007. V. 74. № 6. P. 65–69.

L. I. Bryukvina, S. N. Pidgurskiĭ, E. A. Ermolaeva, and L. F. Suvorova, "Study of the spectral characteristics of surface films of CaF₂ and BaF₂ crystals doped with Eu, Ce, Sm, and Tm by spectroscopic methods," Journal of Optical Technology. 74 (6), 424-427 (2007). https://doi.org/10.1364/JOT.74.000424

This paper discusses films of nanosize particles obtained on the surface of ionic crystals of CaF₂ and BaF₂ with impurities of rare-earth metals Eu, Ce, Sm, and Tm during the thermal diffusion of an intracrystalline impurity. After the CaF₂ crystals are annealed, two bands appear in their optical spectra, with maxima around 270-280 nm and 390 nm, which disappear after a thin surface layer is removed. The surface centers have intense bands at 1100-1150 cm^-1 and 3640 cm^-1 and a moderately intense broad band at 3100-3700 cm^-1 in the IR spectra of the CaF₂ crystals. Intense bands appear at 855-960 cm^-1 in the IR spectrum of the heat-treated BaF₂:Ce crystal, along with the bands at 1100-1150 cm^-1, 3640 cm^-1, and 3100-3700 cm^-1. It is established that the surface centers include impurity ions of a rare-earth metal and the thermal-decomposition products of atmospheric gases.