An ab initio study based on a finite nucleus model for isotope fractionation in the U(III)-U(IV) exchange reaction system
An ab initio study based on a finite nucleus model for isotope fractionation in the U(III)-U(IV) exchange reaction system
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DOI：
10.1063/1.2898541
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发表时间：
2008-04-14
影响因子：
4.4
通讯作者：
Hada, Masahiko
中科院分区：
文献类型：
--
作者：
Abe, Minori;Suzuki, Tatsuya;Hada, Masahiko
用多组态Dirac-Coulomb Hartree-Fock方法对U(III)-U(IV)反应体系中的同位素分馏进行了一系列原子相对论从头计算。为了评价核体积对分馏的影响，采用了费米统计分布函数来描述核电荷密度。根据Bigeleisen[J.Am]提出的理论方程，由U(3+)和U(4+)的总电子能量估算了由核体积差引起的同位素分馏系数e化学。SoC。118、3676(1996)]。本文计算的293K时(235)U和(238)U的分馏系数epsilon为0.0031，与实验值0.0027非常接近。讨论了Pu(III)-Pu(IV)和Eu(II)-Eu(III)交换体系中核体积对同位素分馏的影响。(C)2008年美国物理研究所。
Isotope fractionation in the U(III)-U(IV) reaction system was investigated by a series of atomic relativistic ab initio calculations using the multiconfigurational Dirac-Coulomb Hartree-Fock method. To evaluate the nuclear volume effect on the fractionation, the Fermi statistical distribution function was adopted for nuclear charge density. The isotope fractionation coefficient e resulting from the nuclear volume difference was evaluated from the total electronic energies of U(3+) and U(4+), based on the theoretical equation proposed by Bigeleisen [J. Am. Chem. Soc. 118, 3676 (1996)]. The calculated fractionation coefficient epsilon in the present work for the isotopic pair (235)U and (238)U at 293 K is 0.0031, which is quite close to the experimentally observed value of 0.0027. Discussion is extended to the nuclear volume effects on isotopic fractionations in the Pu(III)-Pu(IV) and Eu(II)-Eu(III) exchange systems. (C) 2008 American Institute of Physics.