Fe_(n)Co_(55-n)与Co_(n)Mo_(55-n)(n=0~55)团簇基态的能量与结构演化  

Energies and structural evolutions of the ground states of Fe_(n)Co_(55-n) and Co_(n)Mo_(55-n)(n=0~55)clusters

作　　者：程彪 郑琪琪 陈轩 段海明[1] CHENG Biao;ZHENG Qi-Qi;CHEN Xuan;DUAN Hai-Ming(School of Physics and Technology,Xinjiang University,Urumuqi 830049,China)

机构地区：[1]新疆大学物理科学与技术学院,乌鲁木齐830049

出　　处：《原子与分子物理学报》2025年第5期57-66,共10页Journal of Atomic and Molecular Physics

基　　金：新疆维吾尔自治区自然科学基金(2022D01C419)。

摘　　要：采用半经验的Gupta多体势函数结合遗传算法及分子动力学淬火算法,系统研究了Co_(n)Mo_(55-n)(n=0~55)与Fe_(n)Co_(55-n)(n=0~55)团簇的基态结构与能量.通过分析基态结构的相似函数、质心间距、平均键长、平均原子配位数、平均结合能、混合能与二阶差分能.探究了团簇基态的结构特征及稳定性与团簇所含元素种类及组分的关联.结果表明:对Co-Mo混合团簇,随Co原子数目增加,Co原子依次占据团簇中心与最外层顶点,混合团簇逐渐出现组分偏析与无序现象;对Fe-Co混合团簇,基态结构主体上均体现为围绕Mackay二十面体构型的结构畸变,随Fe原子含量增加,Fe原子先占据团簇外表面顶点位置直到全部包裹Co原子,逐渐形成核壳式结构;Co_(13)Mo_(42)与Fe_(42)Co_(13)是幻数结构团簇,研究发现组分效应导致的团簇高对称性相比团簇平均键长与平均原子配位数更能解释幻数结构的成因.The ground state structures and energies of Co_(n)Mo_(55-n)(n=0~55)and Fe_(n)Co_(55-n)(n=0~55)clusters were systematically studied by using the semi-empirical Gupta many-body potential combined with genetic algorithm and molecular dynamics quenching algorithm.The similarity function,centroid distance,average bond length,average coordination number,average binding energy,mixing energy and second-order difference energy of the ground state structure are analyzed.The relationship between the structure characteristics and stability of the ground state of the cluster and the types and components of the cluster was investigated.The results show that:for Co-Mo mixed clusters,as the number of Co atoms increases,Co atoms occupy the center and outermost vertices successively,and the segregation and disorder of the mixed clusters gradually appear.For Fe-Co mixed clusters,the main body of the ground state structure is manifested as structural distortion around the Mackay icosahedral configuration.With the increase of Fe atom content,Fe atom occupies the apex position on the outer surface of the cluster until all Co atoms are wrapped,and gradually forms a core-shell structure.Co_(13)Mo_(42)and Fe_(42)Co_(13)are magic number clusters.It is found that the high symmetry of clusters caused by component effects can explain the formation of magic number structures better than the average bond length and the average coordination number.

关 键 词：遗传算法 淬火算法 双金属团簇 基态结构 

分 类 号：O561.1[理学—原子与分子物理]