密度泛函理论对CoBen(n=1—12)团簇结构和性质的研究

采用密度泛函理论中的广义梯度近似(GGA)对CoBe_n(n=1—12)团簇的几何构型进行优化，并对能量、频率和磁性进行了计算，同时考虑了电子的自旋多重度.得到了CoBe_n(n=1—12)团簇最低能量结构的自旋多重度是2和4.在CoBe_n(n=1—12)团簇中，Co原子的磁矩出现了奇偶振荡，当n=6时，Co原子的4s，3d和Be原子的2s，2p较强杂化、Co-Be键长的减小以及对称性的降低导致Co原子的磁矩最小.通过对CoBe_n(n=1—12)团簇电子性质的分析，得出了掺杂可以增强团簇稳定性和有利于增加合金化学活性的结论.n=5，10是团簇的幻数. 关键词： n团簇')" href="#">CoBe_n团簇 自旋多重度 磁矩 电子性质

Density functional theory study on the structure and properties of CoBen(n=1-12) clusters

Geometric structures of CoBe_n(n=1—12) clusters are optimized using the generalized gradient approximation (GGA) density functional theory. The energy, vibrational frequency and magnetism are calculated. The results indicate that the spin multiplicities of the ground-state clusters are 2 and 4. Furthermore, the investigated magnetic moments confirm that the Co atomic magnetic moments of CoBe_n(n=1—12) clusters display an odd-even oscillation feature. In addition, the Co atomic magnetic moments of CoBe₆ is the smallest of all clusters due to the strong hybridization between the 4s, 3d state of Co and 2s, 2p state of Be and short Co-Be average bond distance and low symmetry. By analyzing the properties of electrons, it is concluded that doping of impurity increases the stability and the chemical activity of Be cluster. It is found that CoBe₅ and CoBe₁₀ clusters are more stable than the neighboring ones.