液体和非晶态ni64b36合金结构的从头算分子动力学模拟abinitio.pdfVIP

2005 年第 63 卷 化 学 学 报 Vol. 63, 2005 第 18 期, 1703～1708 ACTA CHIMICA SINICA No. 18, 1703～1708 ·研究论文· 液体和非晶态 Ni64B36 合金结构的从头算分子动力学模拟 祝江波 乔明华 李振华 王文宁 范康年* (复旦大学化学系 上海市分子催化和功能材料重点实验室 化学物理研究中心 上海 200433) 摘要 运用从头算分子动力学模拟了液体以及猝冷后形成的非晶态 Ni64B36 合金体系, 得到了它们的对相关函数、结构 因子、键对分析方面的结构信息, 与实验结果相当一致; 结果表明, 猝冷得到的合金性质与液体合金性质相似, 为非晶 态结构. B 原子多数以 B—B 双原子成键形式分散于 Ni 原子构成的骨架中. 电子态密度分析表明, Ni 3d 电子最活泼, 因 此在合金中 Ni 为活性位. 轨道电荷分析从电子结构角度揭示了在 NiB 催化剂中 B 作为修饰剂的机理. 关键词 从头算分子动力学; 液体 NiB 合金; 非晶态 NiB 合金; 猝冷 Ab initio Molecular Dynamics Simulation of Structures of Ni64B36 Alloys in Liquid and Amorphous Phase ZHU, Jiang-Bo QIAO, Ming-Hua LI, Zhen-Hua WANG, Wen-Ning FAN, Kang-Nian* (Key Laboratory of Molecular Catalysis and Innovative Materials, Center for Chemical Physics, Department of Chemistry , Fudan University, Shanghai 200433) Abstract Liquid and amorphous Ni64B36 alloys were simulated by ab initio molecular dynamics. The sys- tem properties such as pair correlation function, structure factors and bond pair analysis have been obtained, and our results agree with the corresponding experimental ones very well. It is indicated that the amorphous Ni64B36 alloy could be prepared by rapid quenching and its structure is similar to that of liquid alloy. B has been dispersed very well within Ni. The analysis of electronic density of states showed that the d electrons of Ni atoms are the most active, hence Ni atoms are active sites. Orbital popula