四体相互作用对固氦压缩特性的贡献  

Contributions of four-body interactions to compressibility of solid helium

作　　者：田春玲[1] 刘福生[1] 蔡灵仓[2] 经福谦[1] 

机构地区：[1]西南交通大学高压物理实验室 [2]中国工程物理研究院流体物理研究所冲击波物理爆轰物理实验室,绵阳621900

出　　处：《物理学报》2003年第5期1218-1221,共4页Acta Physica Sinica

摘　　要：运用从头计算自洽场方法和原子团簇理论计算了高压下固氦原子间的四体势分量 .计算结果表明四体分量对结合能的贡献为正 ;随着压缩度增大四体势的贡献比例变大 .采用两体、三体、四体势和Aziz吸引势计算固氦零温状态方程并与实验测量相比较 ,结果表明两体势对固氦的压缩性贡献了过多的正效应 ,加入三体分量的修正 ,仅在低于 10GPa时理论值与实验值相符很好 ,但考虑了四体势修正后能将理论值与实验值符合程度提高到 2Based on a mang-body expansion of short-range interatomic force, the four-body interactions in compressed solid helium are computed by ab initio Hartree-Fock self-consistent field technique and the atomic cluster method. It is concluded that four-body terms give a repulsive contribution to the binding energy. By combination of the present many-body expansions with Aziz's long-range attractive potential, the equation of state( EOS) ( T = OK) is calculated and compared with available experimental data. Results emphasize the importance of the four-body interactions in compressed solid He. If only two-body interactions are included such as in the description of the helium gas, the pressure is much overestimated. Good agreement with experiments can only be extended up to about 10 GPa when the three-body corrections are added to; however, the predicted compression curve is obviously lower than that obtained in recent experiments at above 10 GPa. Our study shows that four-body corrections can bring the calculated EOS into a good agreement with experimental data at pressures of 10-27GPa. Our result also implies that the higher-order many-body effects should be taken into account at higher pressures.

关 键 词：四体相互作用 固氦 压缩特性 从头计算自治场方法 原子团簇 四体势 状态方程 

分 类 号：O521[理学—高压高温物理]