Al_mNi_n(m+n=2-4)二元合金团簇结构和稳定性的密度泛函研究

Structures and stabilities of Al_mNi_n(m + n = 2-4)clusters with density functional theory

在密度泛函理论的B3PW91水平上,优化计算了Al_mNi_n(m+n=2-4)团簇的几何结构、团簇基态的结合能、最高占据轨道与最低空轨道之间的能级间隙和可能的分离能.结果表明,随着团簇尺寸的增加,能级间隙呈现奇偶振荡规律;Al_2Ni_2团簇具有最高的结合能,易分离成Ni原子和Al_2Ni团簇;含Al的合金团簇最易先分离出一个Al原子,而含Ni的合金团簇没有这种趋势.

All possible geometrical structures of AlmNin （m＋n=2–4） alloying clusters were optimized at B3PW91 level in density functional theory （DFT）. For the lowest energy structures of AlmNin （m＋n=2–4） clusters, the binding energies, the highest occupied molecular orbital energy levels, the lowest unoccupied molecular orbital energy levels and energy gaps have been calculated. The possible dissociation channels and the corresponding dissociation energies are also analyzed. The results show that the energy gap follows the odd-even oscillate pattern with increasing size; Al2Ni2 has the largest binding energies, which dissociates to Ni and Al2Ni cluster easily; Al–contained clusters prefer to fragment to give one Al atom first, while Ni–contained species have no priority for either Ni to dissociation first.