高度压缩下氢原子团H_n的结构

STRUCTURE STUDY OF HIGHLY COMPRESSED ATOMIC Hn CLUSTERS

本文用ab Initio总能量方法计算了氢原子团H_n在高压下的结构。随着压力的增加,H_n的分子相解体,转变成以四面体为基本结构单元的原子相团簇。计算进一步表明,对于不同的n,团簇的大小是以四面体为其基元的整数倍来排列其结构顺序的,即显示出生长螺旋(growth spiral)特征。从能量稳定性来判断,高压下氢的原子相团簇表现出幻数(magic number)特征。计算的另一个重要结果是,在更高的压缩下,大n的原子团簇将发生破裂,成为H_4和H_5的碎片。这些碎片将密堆积成HCP或fcc结构。

The total energy of various possible closed packing configurations for the Hn (4≤n≤11) clusters was calculated using ab initio all-elctron method. The molecular phases of Hn will be destroyed and will transform into atomic phases. The stuctures of atomic phases of Hn clusters are the closed packing of tetrahedfal units and follow a growth spiral. From the minimum energy criterion, magic number has been found for Hn clusters pressed highly. The increase in the density will cause a depletion larger clusters due to the localization of the electrons, and the structure of metallic hydrogen was predicted to be HCP or fcc.