Energy between trivalent lanthanides

Figure 10 Energy difference between the lowest levels of the 4f and 4f 5d configurations for divalent and trivalent lanthanide ions in fluorite. (Reproduced by permission of Ref. 37)...

Fig. 5. The probability of energy transfer from the uranyl ion to five trivalent lanthanides in phosphate glass as a function of the energy difference between the long-lived uranyl state and the closest J-level below...

The field of lathanide lasers is mature but not exhausted. Additional laser schemes and materials will undoubtedly be exploited. There are 1639 free-ion energy levels associated with the 4fn electronic configurations of the thirteen trivalent lanthanides. Yet, of the 192,177 possible transitions between pairs of levels, by mid-1979 only 41 had been used for lasers. It is certain that given suitable pump sources and materials, stimulated emission involving many... 

FIGURE 16 Energy difference v- ii (in eV per lanthanide ion) between the tetravalent and trivalent lanthanide configurations in dioxides (solid circles) and A-type (hexagonal) sesquioxides (open squares). 

Johansson (1978) and Brooks etal. (1984) utilized the energy difference (f d transitions) between trivalent (f"ds ) and tetravalent (f" M s ) cerium and other f-element metals to estimate thermochemical data for compounds. A similar approach has been used by Mikheev et al. (1986) and Spitsyn et al. (1985) to include the divalent as well as the tetravalent state. Again, a critical issue has been the behavior of the heavy actinides with respect to f- d transitions, and the need to utilize and to interpret the few experimental measurements on these actinides, which are discussed below (e.g., section 2.4.1.3). Johansson and Munck (1984) defined a function P (M) that removes the intershell multiplet coupling energy from the atomic reference state (A ,.,up,i j is the energy difference between the baricenter and the lowest level of a multiplet). For the lanthanides P (M) is significantly smoother than P(M),-except for an anomaly at Yb that may be due to an error in experimental data. Unfortunately, Johansson and Munck (1984) point out that spectroscopic data on the heavy actinides are inadequate to correct P(M) to P (M) for the actinides. 

Recently the luminescence properties of Pr ", Nd, Tm and Yb " ions in fluorite have been obtained by steady-state measurements. In addition, the luminescence spectra of Ce ", Sm ", Sm ", Dy ", Er and Yb were measured. It was pointed out that Xex = 415 nm is most suitable for measuring the Ho " emission beside the Er ". The emission of trivalent holmium and erbium ions was measured independently using time-resolved measurements and tentative assignment of luminescence lines to 3 and C4V symmetry sites was proposed. Besides for natural fluorite crystal, the transition between Stark energy levels of lanthanide ions were presented (Czaja et al. 2012). 

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