Shock Hugoniot of osmium up to 800 GPa from first principles calculations
Shock Hugoniot of osmium up to 800 GPa from first principles calculations
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DOI：
10.1088/0953-8984/21/41/415402
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发表时间：
2009-10
期刊：
影响因子：
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通讯作者：
K. Joshi;S. Gupta;S. Banerjee
中科院分区：
文献类型：
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作者：
K. Joshi;S. Gupta;S. Banerjee
采用FP-LAPW方法，对锇的hcp、ω（三原子简单六方晶系）、β（bcc）和fcc相在流体静压作用下的第一性原理总能量进行了计算.这些相的总能量的比较，直到最大压缩V/V0 = 0.58（压力为700 GPa）表明，hcp结构保持稳定，直到该压缩。300 K等温线是在将有限温度热贡献添加到作为0 K下体积的函数计算的总能量之后确定的。从理论上确定的等温线，我们导出了这种金属的冲击Hugoniot，并确定了冲击参数C 0和s分别为4.48 km s-1和1.32。利用林德曼熔化规则的微分形式的Gruneisen参数，我们确定了锇的熔点随压力的变化。理论推导的熔化曲线和沿Hugoniot的沿着温升预测锇的冲击熔化温度为447 GPa，相应温度为9203 K。
First principles total energy calculations on hcp, ω (a three atom simple hexagonal), β (bcc) and fcc phases of osmium have been performed as a function of hydrostatic compression employing the FP-LAPW method. The comparison of total energies of these phases up to a maximum compression V/V0 = 0.58 (pressure∼700 GPa) shows that the hcp structure remains stable up to this compression. The 300 K isotherm is determined after adding finite temperature thermal contributions to the total energy calculated as a function of volume at 0 K. From the theoretically determined isotherm, we have derived the shock Hugoniot of this metal and determined the shock parameters C0 and s to be 4.48 km s−1 and 1.32, respectively. Employing the theoretically calculated Gruneisen parameter in the differential form of the Lindemann melting rule, we have determined the variation of melting point of the osmium with pressure. The theoretically derived melting curve and the temperature rise along the Hugoniot predict the shock melting of osmium at ∼447 GPa with a corresponding temperature of ∼9203 K.