Khairallah S A, Sevryuk M B, Ceperley D M, Toennies J P
Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
Phys Rev Lett. 2007 May 4;98(18):183401. doi: 10.1103/PhysRevLett.98.183401.
The interplay between magic number stabilities and superfluidity of small parahydrogen clusters with sizes N=5 to 40 and temperatures 0.5 K</=T</=4.5 K is explored with classical and quantum path integral Monte Carlo calculations. Clusters with N<26 and T</=1.5 K have large superfluid fractions even at the stable magic numbers 13, 19, and 23. In larger clusters, superfluidity is quenched especially at the magic numbers 26, 29, 32, and 37 while below 1 K, superfluidity is recovered for the pairs (27,28), (30,31), and (35,36). For all clusters superfluidity is localized at the surface and correlates with long exchange cycles involving loosely bound surface molecules.
通过经典和量子路径积分蒙特卡罗计算，研究了尺寸为N = 5至40且温度为0.5K≤T≤4.5K的小仲氢团簇的幻数稳定性与超流性之间的相互作用。即使在稳定的幻数13、19和23处，N<26且T≤1.5K的团簇也具有较大的超流分数。在较大的团簇中，超流性被猝灭，特别是在幻数26、29、32和37处，而在1K以下，（27,28）、（30,31）和（35,36）对的超流性得以恢复。对于所有团簇，超流性都局限于表面，并且与涉及松散结合的表面分子的长交换周期相关。
