Max Planck Institute for Dynamics and Self-Organization, Bunsenstrasse 10, 37073 Göttingen, Germany.
J Chem Phys. 2010 Aug 14;133(6):064505. doi: 10.1063/1.3458640.
The quantum theorem of corresponding states is applied to N=13 and N=26 cold quantum fluid clusters to establish where para-hydrogen clusters lie in relation to more and less quantum delocalized systems. Path integral Monte Carlo calculations of the energies, densities, radial and pair distributions, and superfluid fractions are reported at T=0.5 K for a Lennard-Jones (LJ) (12,6) potential using six different de Boer parameters including the accepted value for hydrogen. The results indicate that the hydrogen clusters are on the borderline to being a nonsuperfluid solid but that the molecules are sufficiently delocalized to be superfluid. A general phase diagram for the total and kinetic energies of LJ (12,6) clusters encompassing all sizes from N=2 to N=infinity and for the entire range of de Boer parameters is presented. Finally the limiting de Boer parameters for quantum delocalization induced unbinding ("quantum unbinding") are estimated and the new results are found to agree with previous calculations for the bulk and smaller clusters.
对应态量子定理被应用于 N=13 和 N=26 的冷量子流体团簇，以确定 Para-Hydrogen 团簇在更量子离域和较少量子离域系统中的位置。在 T=0.5 K 下，使用 Lennard-Jones (LJ) (12,6) 势能的六种不同 de Boer 参数，包括氢的公认值，报告了能量、密度、径向和对分布以及超流分数的路径积分蒙特卡罗计算。结果表明，氢团簇处于非超流固体的边界，但分子足够离域，可以是超流的。提出了一个涵盖从 N=2 到 N=无穷大的所有大小和整个 de Boer 参数范围的 LJ (12,6) 团簇的总能量和动能的通用相图。最后，估计了量子离域诱导离解的限制 de Boer 参数（“量子离解”），并且发现新结果与体相和较小团簇的先前计算结果一致。
