固体同位素氦混合物的摩尔体积
Molar volume of solid isotopic helium mixtures
摘要：
在等温等压系综中，用路径积分蒙特卡罗模拟研究了固体氦同位素混合物。这种方法使我们能够研究摩尔体积作为温度，压力和同位素组成的函数。在25 K和0.2GPa下，同位素纯的~ 3 He和~ 4 He晶体的摩尔体积之间的相对差异约为3%。这种差异在压力下减小，并且对于12 GPa，其小于1%。对于同位素混合晶体，晶格参数和氦同位素浓度之间的线性关系被发现，符合Vegard定律。虚晶近似对较重原子的同位素混合物有效，但对氦同位素的固溶体不能给出可靠的结果。
英文摘要：
Solid isotopic helium mixtures have been studied by path-integral Monte Carlo simulations in the isothermal-isobaric ensemble. This method allowed us to study the molar volume as a function of temperature, pressure, and isotopic composition. At 25 K and 0.2 GPa, the relative difference between molar volumes of isotopically-pure crystals of 3He and 4He is found to be about 3%. This difference decreases under pressure, and for 12 GPa it is smaller than 1%. For isotopically-mixed crystals, a linear relation between lattice parameters and concentrations of helium isotopes is found, in agreement with Vegard's law. The virtual crystal approximation, valid for isotopic mixtures of heavier atoms, does not give reliable results for solid solutions of helium isotopes.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
