Electronic Structure and Properties of Berkelium Iodates.

Autor: Silver MA; Department of Chemistry and Biochemistry, Florida State University , Tallahassee, Florida 32306, United States., Cary SK; Department of Chemistry and Biochemistry, Florida State University , Tallahassee, Florida 32306, United States., Garza AJ; Department of Chemistry, Rice University , Houston, Texas 77251, United States., Baumbach RE; National High Magnetic Field Laboratory , Tallahassee, Florida 32310, United States., Arico AA; Department of Chemistry and Biochemistry, Florida State University , Tallahassee, Florida 32306, United States., Galmin GA; Department of Chemistry and Biochemistry, Florida State University , Tallahassee, Florida 32306, United States., Chen KW; National High Magnetic Field Laboratory , Tallahassee, Florida 32310, United States., Johnson JA; Environmental Health and Safety, Florida State University , Tallahassee, Florida 32306, United States., Wang JC; Department of Chemistry and Biochemistry, Florida State University , Tallahassee, Florida 32306, United States., Clark RJ; Department of Chemistry and Biochemistry, Florida State University , Tallahassee, Florida 32306, United States., Chemey A; Department of Chemistry and Biochemistry, Florida State University , Tallahassee, Florida 32306, United States., Eaton TM; Department of Chemistry and Biochemistry, Florida State University , Tallahassee, Florida 32306, United States., Marsh ML; Department of Chemistry and Biochemistry, Florida State University , Tallahassee, Florida 32306, United States., Seidler K; Department of Chemistry and Biochemistry, Florida State University , Tallahassee, Florida 32306, United States., Galley SS; Department of Chemistry and Biochemistry, Florida State University , Tallahassee, Florida 32306, United States., van de Burgt L; Department of Chemistry and Biochemistry, Florida State University , Tallahassee, Florida 32306, United States., Gray AL; Environmental Health and Safety, Florida State University , Tallahassee, Florida 32306, United States., Hobart DE; Department of Chemistry and Biochemistry, Florida State University , Tallahassee, Florida 32306, United States., Hanson K; Department of Chemistry and Biochemistry, Florida State University , Tallahassee, Florida 32306, United States., Van Cleve SM; Nuclear Materials Processing Group, Oak Ridge National Laboratory , One Bethel Valley Road, Oak Ridge, Tennessee 37830, United States., Gendron F; Department of Chemistry, University at Buffalo, State University of New York , Buffalo, New York 14260, United States., Autschbach J; Department of Chemistry, University at Buffalo, State University of New York , Buffalo, New York 14260, United States., Scuseria GE; Department of Chemistry, Rice University , Houston, Texas 77251, United States., Maron L; Laboratorie de Physique et Chimie des Nano-objets, Institut National des Sciences Appliquées , 31077 Toulouse Cedex 4, France., Speldrich M; Institut für Anorganische Chemie, RWTH Aachen University , D-52074 Aachen, Germany., Kögerler P; Institut für Anorganische Chemie, RWTH Aachen University , D-52074 Aachen, Germany., Celis-Barros C; Centro de Nanociencias Aplicadas, Facultad de Ciencias Exactas, Universidad Andrés Bello , República 275, Santiago, Chile., Páez-Hernández D; Centro de Nanociencias Aplicadas, Facultad de Ciencias Exactas, Universidad Andrés Bello , República 275, Santiago, Chile., Arratia-Pérez R; Centro de Nanociencias Aplicadas, Facultad de Ciencias Exactas, Universidad Andrés Bello , República 275, Santiago, Chile., Ruf M; Bruker AXS , 5465 East Cheryl Parkway, Madison, Wisconsin 53711, United States., Albrecht-Schmitt TE; Department of Chemistry and Biochemistry, Florida State University , Tallahassee, Florida 32306, United States.
Jazyk: angličtina
Zdroj: Journal of the American Chemical Society [J Am Chem Soc] 2017 Sep 27; Vol. 139 (38), pp. 13361-13375. Date of Electronic Publication: 2017 Sep 14.
DOI: 10.1021/jacs.7b05569
Abstrakt: The reaction of 249 Bk(OH) 4 with iodate under hydrothermal conditions results in the formation of Bk(IO 3 ) 3 as the major product with trace amounts of Bk(IO 3 ) 4 also crystallizing from the reaction mixture. The structure of Bk(IO 3 ) 3 consists of nine-coordinate Bk III cations that are bridged by iodate anions to yield layers that are isomorphous with those found for Am III , Cf III , and with lanthanides that possess similar ionic radii. Bk(IO 3 ) 4 was expected to adopt the same structure as M(IO 3 ) 4 (M = Ce, Np, Pu), but instead parallels the structural chemistry of the smaller Zr IV cation. Bk III -O and Bk IV -O bond lengths are shorter than anticipated and provide further support for a postcurium break in the actinide series. Photoluminescence and absorption spectra collected from single crystals of Bk(IO 3 ) 4 show evidence for doping with Bk III in these crystals. In addition to luminescence from Bk III in the Bk(IO 3 ) 4 crystals, a broad-band absorption feature is initially present that is similar to features observed in systems with intervalence charge transfer. However, the high-specific activity of 249 Bk (t 1/2 = 320 d) causes oxidation of Bk III and only Bk IV is present after a few days with concomitant loss of both the Bk III luminescence and the broadband feature. The electronic structure of Bk(IO 3 ) 3 and Bk(IO 3 ) 4 were examined using a range of computational methods that include density functional theory both on clusters and on periodic structures, relativistic ab initio wave function calculations that incorporate spin-orbit coupling (CASSCF), and by a full-model Hamiltonian with spin-orbit coupling and Slater-Condon parameters (CONDON). Some of these methods provide evidence for an asymmetric ground state present in Bk IV that does not strictly adhere to Russel-Saunders coupling and Hund's Rule even though it possesses a half-filled 5f 7 shell. Multiple factors contribute to the asymmetry that include 5f electrons being present in microstates that are not solely spin up, spin-orbit coupling induced mixing of low-lying excited states with the ground state, and covalency in the Bk IV -O bonds that distributes the 5f electrons onto the ligands. These factors are absent or diminished in other f 7 ions such as Gd III or Cm III .
Databáze: MEDLINE
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