Ag粒子与Ni包覆Ag粒子熔化特性的价键分析  

COVALENT BONDING ANALYSIS ON THE MELTING OF Ag PARTICLE AND Ag PARTICLE EMBEDDED IN Ni MATRIX

作　　者：彭平[1] 韩绍昌[1] 郑采星[1] 金朝晖[2] 胡壮麒[2] 

机构地区：[1]湖南大学材料科学与工程学院,长沙410082 [2]中国科学院金属研究所,沈阳110016

出　　处：《金属学报》2003年第7期673-678,共6页Acta Metallurgica Sinica

基　　金：国家自然科学基金59801011;国家重点基础研究发展规划项目 G2000067105资助

摘　　要：采用非相对论第一原理分子轨道DV—X_α模型簇方法,计算了Ag纳米粒子自由表面与Ag-Ni半共格界面的电子结构,并从键重叠聚居数Q_(AB),层内与层间原子的部分键合强度(PBO)以及界面原子的总键合强度(TBO)几个方面,对Ag的(111),(100)与(110)自由表面和Ag-Ni半共格界面的价键结构进行了比较,进而对其熔化特性进行了分析,初步揭示了自由表面“预熔化”与共格界面“过热”的电子机制,并从电子层次上考察了(111),(100)和(110)表面与界面的预熔化与过热程度及其熔化方式。By using the discrete variation X, (DV-X,,) method, the electronic and bonding structures of Ag particles with (100), (110) and (111) free surfaces and Ag-Ni semi-coherent interfaces were calculated in the framework of the nonrelativistic first-principles theory. Several bonding parameters such as the bond overlap population, the partial bond order of intra-layer and inter-layer as well the local environmental total bond order have been applied to characterize and analyze the melting of Ag free-surface and Ag-Ni semi-covalent interface. This investigation preliminarily reveals the electronic mechanism of pre-melting of free-standing Ag particles and superheating of Ag particles embedded in Ni matrix. And the pre-melting and superheating degree as well melting modes of Ag particles with (100), (110) and (111) free surfaces and Ag-Ni semi-coherent interfaces are also discussed and predicted.

关 键 词：Ag纳米粒子 熔化  DV—Xα法 电子结构 

分 类 号：TG111.5[金属学及工艺—物理冶金] O742.1[金属学及工艺—金属学]