Ground-state splitting of S-state ion Cm3+ in LaCl3

Abstract

An accurate semiclassical method to predict ground-state tunneling splittingsWe report optical-spectroscopic studies of the ground-state splitting of the nominal S-state ion Cm3+ in LaCI 3 . A total splitting of 1.97 ±O.05 cm -1 for the 8 Y 712 ground state of this system has been measured for the first time. Both electric and magnetic dipole transitions were observed. Energy levels of all four Kramers doublets of the 8 Y 7/2 manifold were resolved by means of the site-selective excitation and emission spectra of 8 Y 7/2++6g;7/2 and 8 Y 7/2++695/2 transitions. Our results show that the lowest component of the ground manifold is a JL=5/2 state dominated by M = I ± 7/2) in contrast to a previously reported JL = 1/2 state. The crystal-field model, established through analyzing optical spectra of the excited states, predicts a groundstate splitting with the right ordering but greater magnitude. In comparison with the lanthanide S-state ion Gd3+, much stronger spin--orbit coupling and reduced electrostatic interaction in concert with greater crystal field interaction significantly influence the characteristics of the ground state of the actinide S-state ion. Contributions from within the 5f7 configuration account for most of the observed splitting.

Systematics of f-element crystal-field interaction

“…Particularly, interpretation of the crystal-field splitting of the nominal 8 S 7/2 ground state in a half-filled shell of the f 7 configuration was contradictory in the history of felement spectroscopy [14,51,[59][60][61][62]. The lanthanides in such a configuration are Eu 2+ , Gd 3+ , and Tb 4+ ; and the actinide ions include Am 2+ , Cm 3+ , and Bk 4+ .…”

“…Fig. 5 shows the correlation of the crystal-field strength N 0 v with free-ion interaction parameters F 2 and z 5f ; and the shift of the center of gravity for two multiplets of Cm 3+ in LaCl 3 [51], LuPO 4 [45,52], CsCdBr 3 [53], Cs 2 NaYCl 6 [54], and ThO 4 [55]. A trend is evident that the values of F 2 and z 5f and the center of gravities E ave ( 6 D 0 7/2 ) and E ave ( 6 P 0 5/2 ) decrease with increasing crystal-field strength, N v 0 .…”

Curium(III) Borate Shows Coordination Environments of Both Plutonium(III) and Americium(III) Borates

“…The crystal field interaction of Cm 3+ in 5f 7 configuration is weak especially in the ground state and low-lying excited states. [8] The energy levels of these states are relatively insensitive to the lattice environment. Figure 3 shows the site-resolved fluorescence emission spectra of Cm 3+ excited resonantly from the ground multiplet 8 S 7/2 into the emitting state of 6 D 7/2 mixed with 6 P 5/2 .…”

“…Like Gd III , Cm III has a half-filled f shell with seven unpaired electrons. However, the spin-orbit coupling is much stronger in Cm III than in Gd III , [8] so its electronic properties are absolutely unique. Curium is the only f-block element, whose magnetic interactions can control its crystal structure.…”

5f−6dorbital hybridization of trivalent uranium in crystals of hexagonal symmetry: Effects on electronic energy levels and transition intensities

“…41 A small and negative B 0 2 ͑f f͒ from our calculation is consistent with previous calculations and experiments on Cm 3+ : LaC 3 and other systems. 36,42,43 Based on these agreements, we believe that the calculated values for the odd crystal-field parameters B q k ͑fd͒ should also be reliable and provide a correct interpretation of the spectroscopic effects induced by configuration mixing.…”