团簇Ni_3CoP的结构和热力学稳定性

Study on structure and thermal stability of cluster Ni_3CoP

为深入了解非晶态合金Ni-Co-P的性质,以团簇Ni_3CoP为模型,基于密度泛函理论对其进行多方面的分析,包括稳定存在的构型、各构型所占比例、各种能量参数等以探究其稳定性,发现团簇Ni_3CoP除构型5(1)为戴帽三角锥型外,其余所有稳定存在的构型均为三角双锥型。单重态各构型和三重态各构型所占比例变化及各种能量参数的变化均比较平缓,但在单重态构型1(1)与三重态构型4(3)之间出现剧变点,团簇Ni_3CoP能稳定存在的临界能量约为-659.450 a.u。从能量学的角度看,多重度的改变对团簇Ni_3CoP构型的稳定性有较大影响,三重态构型的稳定性均好于单重态构型,构型1(3)所占比例最高,能量最低,结合能最大,吉布斯自由能变最小,是团簇Ni_3CoP最有可能稳定存在的形式。

To further understand the properties of amorphous Ni-Co-P alloy,the structures and their thermal stability are studied by using cluster Ni3CoP as a model according to density functional theory,and the possible structure of stable configurations,the proportion of each stable configuration and various energy parameters are analyzed. It is found that the structure of all the stable configurations of cluster Ni3CoP is trigonal bipyramid except the configuration 5（1）which is hooded triangular cone. Proportion and energy parameters＇ s changes of each stable configuration in singlet state and triplet state are not obvious. The sharp changing point between configuration 1（1）and configuration 4（3）is observed. The critical energy of the stable existence of the cluster Ni3CoP is about-659.450 a.u. The change of configurations＇ multiplicity has a big influence on the stability of cluster Ni3CoP. Configurations in triplet state are more stable than those in singlet state. The configuration 1（3）is the stablest structure of cluster Ni3CoP due to the greatest proportion,the lowest energy,the biggest binding energy and the smallest Gibbs free energy.