The High Resolution 4f-5d Absorption Spectrum of Divalent Dysprosium (Dy2+) in Strontium Chloride Host SrCl2 - Fine Structure and Zero-phonon Transitions Revealed

The virtual lack of information on electronic spectra of divalent lanthanide elements (Ln2+) other than Sm2+, Eu2+, Tm2+ and Yb2+ has prompted us to set for synthesis and characterization of novel Ln2+ systems. First successful attempt concerned SrCl2:Nd2+ single crystals. Here, we report stabilization of divalent dysprosium in a chloride host. Importantly this has been accomplished with Dy ions introduced in a divalent state during synthesis, unlike by -irradiation of Dy3+ systems employed previously. This synthesis method yields good quality SrCl2:Dy2+ single crystals. The electronic absorption spectra of Dy2+ doped in SrCl2 have been recorded with high resolution at liquid helium temperature (4.2 K). Identification of the absorption bands occurring in the spectral range of 5000 - 45000 cm-1 is achieved. Based on theoretical calculations using semi-empirical Hamiltonian model, assignment of bands and determination of the Hamiltonian parameters for Dy2+(4f95d1) configuration is carried out. The experime...