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The laser induced fluorescence spectrum of K2YF5:Nd3+ (PFYK:Nd) single crystal, pumped by the fluorine F2 pulsed discharge molecular laser at 157.6 nm, was obtained in the Vacuum Ultraviolet (VUV) region of the spectrum. The fluorescence peaks were assigned to the 4f25d yields 4f3 dipole allowed transitions of the Nd3+ ion. The absorption spectrum of the PFYK:Nd crystal samples in the VUV spectral region was obtained as well. The transitions between the 4I9/2 ground level of the Nd3+ ion of 4f3 configuration and the levels of 4f25d configuration were observed for these crystal samples, to our knowledge for first time. The electric crystal field splits all the levels of single and mixed configuration. The number and the spacing of the components depends on the symmetry and the intensity of the crystal field. We found that the 4f25d levels of the Nd3+ ion, split into eight components in the PFYK host lattice. The edge of the 4f25d levels of the Nd3+ ion in the PFYK crystal host was found to be at 54940 cm-1. Furthermore, we report on the interconfigurational 4f25d yields 4f3 VUV fluorescence characteristics of the PFYK:Nd crystal under excitation form the pulsed discharge F2 molecular laser operating at 157.6 nm. The concentration of the Nd3+ ions in the crystal sample was 0.1 percent. The sample was an optically polished disk having a diameter of 5 mm and thickness of 1.2 mm. The experimental set up consisted mainly of the F2 pulsed discharge molecular laser, a hydrogen lamp, an XUV- VUV monochromator, and the necessary electronic equipment for detecting and recording the spectrum. The laser source delivers 12 mJ per pulse and only 1 mJ, after focusing, was used to excite the crystal samples. The spectra were detected with a resolution better than 0.5 nm.
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