C72,La2@C72几何结构和电子性质的计算研究

采用密度泛涵理论(density functional theory, DFT)中的广义梯度近似(generally gradient approximation, GGA)对富勒烯C₇₂和内掺金属La富勒烯La₂@C₇₂三种同分异构体的几何结构和电子结构进行研究.发现在C₇₂的三种同分异构体中，满足独立五边形规则(isolated-pentagon-rule，IPR)的C₇₂(D_{6d< 关键词： 72}')" href="#">C₇₂ 2@C₇₂')" href="#">La₂@C₇₂ 密度泛涵理论 几何结构 电子结构

Structural and electronic properties of C72 and La2@C72

The geometric and electronic properties of the three isomers for C₇₂ and La₂@C₇₂ have been studied using the generalized gradient approximation in density functional theory (DFT). It is found that C₇₂(D_6d) which satisfies the isolated-pentagon rule is the most stable structure among the three isomers of C₇₂, while La₂@C₇₂ (#10611) is the most stable structure and La₂@C₇₂ (D_6d) is the most unstable structure among the three isomers of La₂@C₇₂. It is also found from the analysis of energy levels as well as the density of states that the stability change is due to the mixing of La atomic orbital with C atomic orbital in C₇₂. From Milliken populations, we find that there are about three electrons transferring from the two encaged La atoms to C₇₂ cage so the electronic configuration of La₂@C₇₂ (#10611) can be described as La³⁺₂@C^3-₇₂. We also come to the conclusion from the net spins of La as well as of La₂@C₇₂ that the magnetic moments of La have been completely quenched so La₂@C₇₂ (#10611) shows no magnetism.