一种适于大尺度复杂纳米体系材料模拟的半经验哈密顿方法  

Material modeling for large scale and complex nanostructures:A semi-empirical Hamiltonian method

作　　者：虞明[1] 吴式玉 

机构地区：[1]美国肯塔基州路易斯维尔大学物理系

出　　处：《物理学报》2015年第18期167-198,共32页Acta Physica Sinica

基　　金：美国国家自然科学基金(批准号:NSF-DMR-0112824);美国能源部研究基金(批准号:DE-FG02-00ER45832);美国陆军(SMDC)研究基金(批准号:W9113M-04-C-0024);美国肯塔基州科学及工程基金(批准号:KSEF-753-RED-007)资助的课题~~

摘　　要：本文综述介绍了近来发展的一种具有可靠性、普适性和预测性的半经验哈密顿方法.该哈密顿在原子轨道的线性组合(LCAO)框架下同时引入了电荷自洽及环境因素(SCED),称之为SCED-LCAO哈密顿.由于SECD-LCAO哈密顿囊括了电荷自洽重组、电子屏蔽效应以及多体环境的影响,使得该方法可以更加准确地描述在复杂结构重组中化学键的成键与断键过程.其动力学计算可用于模拟大尺度复杂纳米体系的结构特性、电子性能以及复杂结构的重组过程.我们已经用此方法成功地解释了不同种类碳团簇纳米结构的相对稳定性和bucky-diamond结构碳团簇的热力学相变,揭示了碳管生长的初始机理,系统地研究了碳化硅纳米线的构型与能量之间的关系及其电子性能,发现了碳化硅笼状结构的特征,尤其是碳化硅笼状结构的动力学自动组装功能,并预示了bucky-diamond结构的碳化硅团簇存在的可能性.最近,该方法引入了与环境关联的轨道占据因素,并成功地运用到研究具有三价电子特性的多构硼元素体系中,准确地描述了硼元素的复杂化学成键特性、同类异性结构以及不同种类硼团簇纳米结构的相对稳定性.The advent of the era of nano-structures has also brought about critical issues regarding the determination of stable structures and the associated properties of such systems.From the theoretical perspective,it requires to consider systems of sizes of up to tens of thousands atoms to obtain a realistic picture of thermodynamically stable nano-structure.This is certainly beyond the scope of DFT-based methods.On the other hand,conventional semi-empirical Hamiltonians,which are capable of treating systems of those sizes,do not possess the rigor and accuracy that can lead to a reliable determination of stable structures in nano-systems.During the last dozen years,extensive effort has been devoted to developing methods that can handle systems of nano-sizes on the one hand,while possess first principles-level accuracy on the other.In this review,we present just such a recently developed and well-tested semi-empirical Hamiltonian,referred in the literature as the SCED-LCAO Hamiltonian.Here SCED is the acronym for self-consistent/environment-dependent while LCAO stands for linear combination of atomic orbitals.Compared to existing conventional two-center semiempirical Hamiltonians,the SCED-LCAO Hamiltonian distinguishes itself by remedying the deficiencies of conventional two-center semi-empirical Hamiltonians on two important fronts：the lack of means to determine charge redistribution and the lack of involvement of multi-center interactions.Its framework provides a scheme to self-consistently determine the charge redistribution and includes multi-center interactions.In this way,bond-breaking and bond-forming processes associated with complex structural reconstructions can be described appropriately.With respect to first principles methods,the SCED-LCAO Hamiltonian replaces the time-consuming energy integrations of the self-consistent loop in first principles methods by simple parameterized functions,allowing a speed-up of the self-consistent determination of charge redistribution by two orders of magnitudes.Thus the m

关 键 词：半经验哈密顿方法 电荷自洽及重组 多体环境影响 大尺度复杂纳米材料 

分 类 号：TB383.1[一般工业技术—材料科学与工程] TQ163.4[化学工程—高温制品工业]