标题： 纳米晶态正氢团簇在石墨上的交换驱动自扩散 显示英文标题

标题： Exchange-driven self-diffusion of nanoscale crystalline parahydrogen clusters on graphite

摘要： 计算机模拟提供了在低温下吸附在石墨基底上的纳米尺度对氢簇的超流行为的证据 ($T\lesssim 0.25 \text{ K}$). 分子数在7到12之间的簇同时表现出超流性和晶体有序性，反映了基底的起伏。 值得注意的是，发现分子数在7到12之间的特定簇在表面上像自由粒子一样自扩散，尽管基底有强烈的钉扎效应。 这种效应是由相同分子集团的协调量子力学交换所引起的，即它没有经典对应物。 显示英文摘要

摘要： Computer simulations yield evidence of superfluid behavior of nanoscale size clusters of parahydrogen adsorbed on a graphite substrate at low temperature ($T\lesssim 0.25 \text{ K}$). Clusters with a number of molecules between 7 and 12 display concurrent superfluidity and crystalline order, reflecting the corrugation of the substrate. Remarkably, it is found that specific clusters with a number of molecules ranging between 7 and 12 self-diffuse on the surface like free particles, despite the strong pinning effect of the substrate. This effect is underlain by coordinated quantum-mechanical exchanges of groups of identical molecules, i.e., it has no classical counterpart.