Repulsive Potential and Their Multi-Body Expansion of Compressed Atomic Cluster Hen (n＝3, 4, 5)
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摘要: 采用Lowdin方法计算了处于压缩状态的氦原子团簇Hen（n＝3，4，5）的排斥势及其多体展开分量。发现随原子数目或压缩度增大，多体展开式的收敛性变差。多体展开式中两体势分量、四体势分量为正值，三体势分量和五体势分量为负值。因此，在进行近似处理时，两体近似法计算的排斥势偏高。经三体修正后的排斥势必然偏低。该计算结果与最新的实验结果定性符合。发现四体势和五体势分量对高密度氦状态方程仍然具有重要贡献。Abstract: Lowdin scheme is applied to calculate the repulsive potentials and their multi-body expansion of compressed atomic clusters Hen (n＝3, 4, 5). It is found that the multi-body expansion converges more slowly as the members of atoms and compression increase. In multi-body expansion, the two-body and four-body contributions are repulsive and the three-body and five-body contributions are attractive. Therefore, when we treat many-body interaction by means of multibody expansion approach, the two-body approximation always overestimates repulsive potentials and three-body corrections soften system too much. These results agree with the new experiments. It is also found that the four-body and five-body contributions are important for the equation of state of dense helium.
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Key words:
- repulsive potential /
- dense helium /
- multi-body expansion /
- atomic cluster
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