Behavior of actinide dioxides under pressure:: UO2 and ThO2 -: art. no. 014113
Behavior of actinide dioxides under pressure:: UO2 and ThO2 -: art. no. 014113
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DOI：
10.1103/physrevb.70.014113
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发表时间：
2004-07-01
影响因子：
3.7
通讯作者：
Rebizant, J
中科院分区：
文献类型：
--
作者：
Idiri, M;Le Bihan, T;Rebizant, J
ThO2 和 UO2 的结构高压特性已在金刚石砧室中进行了研究，最大压力分别为 80 和 69 GPa。这些结果表明，钍和二氧化铀在压力下表现出相同的结构转变序列。两者都相当缓慢地转变为铜矿型（斜方晶系 Pnma）高压结构。这项研究是在比以前的实验更好的静水条件下进行的，使我们能够确定两种二氧化物的可靠压缩性参数：ThO2：B-0=198(2) GPa 和 B-0(')=4.6(3)； UO2: B-0=207(2) GPa 且 B-0(')=4.5(4)。在 UO2 的情况下，环境压力立方相在 69 GPa 下仍然存在，这与早期的测量结果相矛盾。根据这些结果以及对其他二氧化锕系 PuO2 和 AmO2 进行的重新计算，我们通过二氧化锕系系列获得了不同的体积模量演变。
The structural high-pressure properties of ThO2 and UO2 have been studied in diamond-anvil cells up to maximum pressures of 80 and 69 GPa, respectively. These results show that both thorium and uranium dioxides exhibit an identical sequence of structural transitions under pressure; both transform rather sluggishly to the cotunnite-type (orthorhombic Pnma) high-pressure structure. This study which was performed under better hydrostatic conditions than previous experiments has enabled us to determine reliable compressibility parameters for the two dioxides: ThO2: B-0=198(2) GPa and B-0(')=4.6(3); UO2: B-0=207(2) GPa and B-0(')=4.5(4). In the case of UO2 the ambient pressure cubic phase was still found to be present at 69 GPa, which is in contradiction with earlier measurements. With regards to these results and re-calculations performed on other actinide dioxides PuO2 and AmO2, we obtain a different evolution of the bulk moduli through the actinide dioxide series.