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Influences of nuclear mass, size, shape and spin on chemical isotope effect of titanium

1998; Volume: 102; Issue: 12 Linguagem: Inglês

10.1002/bbpc.19981021220

0005-9021

Toshiyuki Fujii, Jun Inagawa, Kazushige Nishizawa,

Boron Compounds in Chemistry

Abstract Titanium isotopes of Ti (III) or Ti (IV) were fractionated by liquid‐liquid extraction system using dicyclohexano‐18‐crown‐6. The nuclear size and shape effect and the nuclear spin effect resulted in the breakdowns of the linear dependency of the enrichment factors to the mass difference. The nuclear mass effect, the nuclear size and shape effect and the nuclear spin effect were calculated by the isotope pair evaluation method. The nuclear mass effects were 0.000634 for 48 Ti‐ 46 Ti (III) and 0.000559 for 48 Ti‐ 46 Ti (IV), where the total enrichment factor were 0.000989 and −0.000166, respectively. The nuclear size and shape effects were 0.000356 for 48 Ti‐ 46 Ti (III) and −0.000725 for 48 Ti‐ 46 Ti (IV). The nuclear spin effects were 0.000180 for 47 Ti (III), 0.000369 for 49 Ti (III), −0.000303 for 47 Ti (IV) and −0.000526 for 49 Ti (IV). The ratio of chemical effect given by the field shift of 3d‐orbital to that of 4s‐orbital was −1.54, which had same direction and quantity with the field shift ratio of 3d‐orbital to 4s‐orbital in Ti I in atomic spectra. This showed that the nuclear size and shape effect on the chemical isotope effect directly reflected the field shifts of Ti I. The nuclear spin effect was the function of the number of the hyperfine splitting vibrational energy levels and the coordination number. This effect was found when the coordination numbers differ nonstoichiometrically between the aqueous phase and the organic phase.