Nuclear Size and Shape Effect in Chemical Isotope Effect of Gadolinium Using Dicyclohexano-18-Crown-6

Abstract

Gadolinium isotopes were fractionated in a liquid-liquid extraction system using dicyclohexano-18-crown-6.The isotope enrichment factors showed breakdowns of the conventional Bigeleisen-Mayer approximation for every condition of the initial phases; the concentrations of gadolinium and hydrochloric acid and the type of organic solvents. The nuclear mass effect and the field shift effect were estimated by use of the isotope pairs 152Gd_I60Gd and 154Gd_16°Gd. Since both isotopes.P'Gd and 154Gd, have the unique characteristics of the nuclear charge radii, <r'>'s, the unusual isotope effects due to the field shifts took place, while the mass effects of the other isotopes canceled the field shift effects. The maximum isotope effect was observed to be 6160.152 = 0.0252 ± 0.0024 whose initial aqueous phase was 0.023 M GdCl, in 12 M HCl, and its organic phase was 0.2 M DC18C6 in chloroform: this was 0.00315 ± 0.00030 in terms of the enrichment factor for unit mass. 1219

Difference in the stable isotopic fractionations of Ce, Nd, and Sm during adsorption on iron and manganese oxides and its interpretation based on their local structures

“…Ce 4+ reaction may be due to nuclear-volume isotope fractionation, the Ce/ferrihydrite system was unaffected here by the oxidation reaction. A nuclear-volume driven effect was also reported for Nd and Sm (Fujii et al, 1998(Fujii et al, , 2000, but the current study shows that the d 145 Nd vs. d 146 Nd and d 149 Sm vs. d 152 Sm correlations are in accord with a purely mass-dependent isotope effect (Figs. EA2 and EA3), meaning that nuclearvolume driven fractionation was negligible in the experiments.…”

Nuclear field shift effect as a possible cause of Te isotopic anomalies in the early solar system—An alternative explanation of Fehr et al. (2006 and 2009)

“…These have been confirmed experimentally by chemical exchange methods (solvent extraction or liquid chromatography) with macrocyclic compounds (Fujii et al 1998a(Fujii et al , 1998b(Fujii et al , 1999(Fujii et al , 2001(Fujii et al , 2002a(Fujii et al , 2002b(Fujii et al , 2006bMoynier et al 2008Moynier et al , 2009.…”

Strontium Isotope Effects Observed in Liquid Chromatography with Crown Ether Resins

“…The elements studied include lithium, 1) magnesium, 2) zinc, 3) nickel, 4) samarium, 5) neodymium, 6) gadolinium, 7) strontium, 8) barium, 9,10) chromium, 11) iron, 12) molybdenum, 13) and hafnium. 14) These studies revealed that crown ethers often show large isotope effects, indicating that they could provide isotope separation systems with high performance.…”