Ni-B非晶态合金中电子转移问题的DFT研究

DFT Study of Electron Transfer between B and Ni in Ni - B Amorphous Alloy

根据Ni-B非晶态结构的短程有序、Ni和B之间是较强的化学作用和结构中存在B-B直接相连的实验事实,选择了Ni_mB_2^(1)(m=1～4)原子簇模型,用DFT方法对其进行高水平的量子化学计算,结果表明,模型体系中,B原子供给Ni原子电子,这与非晶态合金的实验结果一致,为了比较,同时选择了Ni_mB^(2)(m=1～4)模型,计算结果与实验不符,这说明Ni_mB^(1)_2(m=1～4)原子簇模型更能反映非晶态的结构特点.

The electron transfer between B and Ni is an open problem in the study of Ni - B amorphous alloy. This problem is very important in the understanding of the alloy' s catalytic behavior and other related properties. In order to model the structure of Ni - B amorphous alloy, NimB2(1) ( m = 1 ~ 4) cluster models were chosen according to the experiment observations for the presence of direct B - B contact, a very strong interaction between Ni and B and short - range - ordering in the amorphous alloy. NimB2(1)(m = 1 ~ 4) cluster models were calculated with DFT method. Several proposed geometries were optimized, and then their population and binding properties were also analyzed. The results of the calculations and analysis show that boron is an electron - donor in the Ni - B amorphous alloy, while nickel is an electron - acceptor, which agrees well with the experimental results. Compared with the calculation results from another series of NimB(2)(m = 1-4) cluster models, it can be concluded that the NimB2(1)( m = 1 ~ 4) clusters is more reasonable for the structure of Ni - B amorphous alloy.