原子簇Ni2Fe2P结构稳定性的密度泛函理论研究

利用DFT(密度泛函理论)方法在B3LYP/Lan12dz水平下对原子簇模型Ni₂Fe₂P的二十余种可能构型分别在二、四重态下进行优化计算,分析比较了优化结果的能量、结合能、吉布斯自由能变化和过渡态.结果表明:原子簇Ni₂Fe₂P十种异构体没有虚频,有可能稳定存在于非晶态合金中;其中以具有二重态的构型1的能量最低,结合能、吉布斯自由能变化及过渡态能垒最大,最为稳定;四重态中异构体1',2',3'和4'共存的可能性比较大.

Density Functional Theory Study on Structure and Stability of Cluster Ni2Fe2P

Amorphous alloy has attracted extensive interest owing to its unique local structure and novel chemical properties since 1960s. However to research in laboratory is very difficult because of its complex structure and transience of growth process. Hence it is of profound significance to use suitable model to correctly simulate the local structure and electronic properties of amorphous alloys. In present paper, a series of clusters Ni2Fe2P were designed, which were primitive models for the ternary amorphous alloy Ni40Fe40P20, and optimized with density functional theory at B3LYP/Lan12dz level to gain the stable structure and the transition of isomers. After analysis and discussion, the results show that the binding energies of isomers were all above zero, and all the isomeric changes of Gibbs free energy were negative in the growth path of cluster Ni2Fe2P. The energy change of configuration 1 with doublet state was larger than others. Namely, each isomer could exist probably in amorphous alloys and configuration 1 is more stable than other isomers. The energy of activation also proved the conclusion. Because of the little difference of activation energy, it is easy to process isomerism reaction for them, which are the four lowest energy configurations with quartet state. And the isomerism is difficult to isomerize from the three-dimensional configuration to plane.