固体C_（70）取向相变的理论研究  

A THEORETICAL STUDY OF ORIENTATIONAL TRANSITION IN SOLID C_(70)

作　　者：辛厚友 杨灵法[1] 

机构地区：[1]中国科学技术大学化学物理系

出　　处：《低温物理学报》1995年第3期166-171,共6页Low Temperature Physical Letters

摘　　要：本文利用转子函数研究了固体Ｃ＿（７０）的取向相支，转子函数同时兼顾了分子的Ｄ（５ｈ）对称性以及面心立方晶格的Ｏｈ对称性．我们提出的分子间相互作用势模型除考虑了原子一原子间Ｌｅｎｎａｒｄ－Ｊｏｎｅｓ势的基本作用外还特别注意到了库仑作用，它是由不同分子上沿键的富电荷区与五边形、六边形中心缺电荷区的相互作用引起的，计算表明，ｌ＝２的Ｔ（２ｇ）模的模间耦合的消失及ｌ＝５的Ｔ１ｕ（２）模间耦合的消失分别对应该体系３３０Ｋ和２７０Ｋ处发生的两次取向相变，由此计算出的取向相变温度与实验值相当．Abstract Orientational transitions in solid C70 have been studied in terms of rotator functions which the molecular symmetry D5h and the fee lattice symmetry O^are taken into account. An intermolecular interaction model is proposed, considering both atom-atom Lennard-Johns potentials and Coulombic forces resulting from high-electron density regions along edges and low-electron density regions at the centers of pentagons and hexagons of the molecule. The disappearance of coupling of the active modes T1g of l=2 and T1u of l= 5 manifolds results in two orientational transitions at 330K and 270K, respectively. The calculated values agree with experimental values.

关 键 词：富勒烯 转子函数 取向相变 碳70 

分 类 号：O613.71[理学—无机化学] O511.1[理学—化学]