采用密度泛函理论框架下的赝势平面波法,计算了δ-Pu在基态和高压下的晶格常数、结合能、力学性能以及电子结构。计算结果表明δ-Pu为高压不稳定相,在10GPa左右就会发生相变,且随压强增大,其结构稳定性降低。通过对电子结构的分析,发现随压强的增大,5f和6d电子的成键能力增强,但sp杂化作用减弱。压强增大导致的成键作用变化,揭示了δ-Pu高压相变的电子机制。

The lattice constants,cohesive energy,mechanical property and electronic structure of δ-Pu at the ground state and high pressure were calculated by a plane wave pseudo-potential method based on the density functional theory.The result shows that δ-Pu is unstable at high pressure and the phase transition occurs at about 10 GPa.In addition,its structural stability decreases with increasing pressure.The calculated electronic structures indicate that the bonding abilities of the 5f and 6d electrons are enhanced,while the sp hybridization is weakened with the pressure increasing.The change in the bonding effect caused by the increase in pressure reveals the electronic mechanism of the pressure-induced phase transition of δ-Pu.