氯化镁熔盐的分子动力学模拟

根据包括离子间极化作用势在内的离子间热对氯化镁熔盐做了分子动力学模拟，计算出的偏径向分布函数与中子衍射结果大致符合，计算机结果表明，熔体中存在微观分布不均匀的缝隙，Ｍｇ＾２＋周围的Ｃｌ＾－离子数分布在２与６之间，熔盐含有ＭｇＣｌ３＾－和ＭｇＣｌ＾２４－离子。     

Li,K|F,Cl互易系熔盐溶液的分子动力学计算机模拟研究

用分子动力学方法对Li,K?F,Cl系熔盐溶液进行了计算机模拟研究。计算了径向分布函数、偏克分子混合能等热力学性质以及Li~+,K~+,F~-和Cl~-的扩散系数。计算值与实验值大体符合。根据计算结果,讨论了熔盐溶液中离子和空孔分布的规律。     

NaF-AlF_3系熔盐结构的分子动力学计算

使用Born Mayer Huggins(BMH)型势函数 ,用分子动力学 (MD)方法模拟计算了 (NaF) x(AlF3) 1-x(x=0 .8,0 .75 ,0 .6 7,0 .5 )熔盐体系在 132 3K时的结构 ,得到了径向分布函数、F Al F键角分布等结构信息 ,其中各熔体的F Al F键角分布呈现相似的特征 ,在 80°～ 90°之间和 16 0°～ 170°之间出现峰值。统计了由平衡构像所得到的熔体中Al F的配位情况 ,结果证实在所得势函数作用下 ,熔体中主要基团形式是AlF3-6八面体 ,其中桥氟在结构形成中起很大作用 ,NaAlF4 熔体中的铝氟八面体通过氟桥连接成较大的集团或空间网络     

熔融LiF—BeF_2体系的定压分子动力学模拟

用定压分子动力学模拟,研究了熔融LiF—BeF_2,LiF—2BeF_2和LiF—3BeF_2体系。分析了模拟给出的径向分布函数、配位数、键长以及扩散系数和速度自相关函数。所得主要结果是:BeF_2体系原来存在的网络结构,随Li~+离子的浓度增加而削弱和破坏,但并不接近LiF结构。     

NaF—CaF2熔盐溶液结构的分子动力学模拟研究

使用分子动力学方法,研究了NaF—CaF_2熔盐体系给出了体系各离子间的偶对分布函数和各种健角几率分布,并在此基础上讨论了体系中的桥和络合模拟结果表明,Ca~(2+)离子周围的F~(-)离子未形成四面体配位,出现象CaF_4~(2-)这样小的络合原子团的可能性不大Ca~(2+)离子周围F~(-)离子排布的一种可能的结构是3个Ca~(2+)离子通过F~(-)离子桥联成一个正三角形,正三角形中心上下各有一个F~(-)离子,每个Ca~(2+)离子在三角形外侧还各有2个F~(-)离子     

Li,K|F,Cl互易系熔盐溶液的分子动力学计算机模拟研究SCIEI

用分子动力学方法对Li,K?F,Cl系熔盐溶液进行了计算机模拟研究。计算了径向分布函数、偏克分子混合能等热力学性质以及Li^+,K^+,F^-和Cl^-的扩散系数。计算值与实验值大体符合。根据计算结果,讨论了熔盐溶液中离子和空孔分布的规律。     

熔融NaF的分子动力学模拟研究

本文用分子动力学方法对熔融NaF进行了计算机模拟研究。离子间相互作用势采用两种形式。其一是Fumi-Tosi(FT)势;其二是不计入Vander Waals引力的FT势(记为FT′),计算了径向分布函数以及Na~+,F~-的自扩散系数。计算结果与实验值很好相符。计算结果表明,两种势函数给出的模拟结果对径向分布函数和扩散系数无显著影响,但FT势比FT′势有所改善。     

NiAl热诱发马氏体相变的分子动力学模拟

运用ＮｉＡｌ合金的镶嵌原子势，进行了Ｂ２结构ＮｉＡｌ中热诱发马氏体相变的分子动力学模拟，从而研究马氏体形核和长大的微观机理．首先进行了０Ｋ等体积条件下ＮｉＡｌ的相稳定性分析，发现０Ｋ时点阵参数ｃ与ａ之比约为１．３１的ｂｃｔ结构是稳定结构，Ｂ２结构只是一种亚稳结构．在热诱发马氏体相变的模拟过程中，由于ＮｉＡｌ中Ｎｉ原子和Ａｌ原子的振动性质存在着差异，造成了马氏体的不均匀形核．对另两种不同初始构型的系统进行的模拟进一步证实了不均匀形核的存在，并通过计算Ｂ２结构ＮｉＡｌ中Ｎｉ原子和Ａｌ原子的热运动均方位移解释了其原因．模拟中，Ｂ２结构奥氏体经热诱发马氏体相变转变为ｆｃｔＬ１_０结构的马氏体．马氏体在长大过程中内部形成了若干转变孪晶．     

COMPUTERIZED SIMULATION OF MOLTEN SALT SOLUTION OF Li,KF,Cl SYSTEM BY MOLECULAR DYNAMIC METHOD

The structure and properties of molten salt solution o J Li,K|F,Cl system have been investigedby computerized simulation of molecular dynamic method.The partial RDF,the partial molarenergy of mixing and the diffusion coeffients of Li~+,K~+,F~- and Cl~- have been calculated.The results are in agreement with the experimental values.The regularities of the distributionof ions and mieroscopic holes are discussed based on the results of computerized simulation.     

LiF-KF熔盐溶液热力学性质Monte Carlo法计算机模拟研究

本文用 Monte Carlo法对同离子系LiF-KF熔盐溶液的结构和性质进行了计算机模拟.对各离子间的偏径向分布函数和混合热、位能分布等的计算表明,LiF与KF熔盐混合后,Li~+,F~-离子间平均距离减少,与互易盐系LiF-KCl溶液的模拟结果相似.混合热的计算结果与实测值相当接近。混合热产生的原因:正离子间排斥能减少;正负离子间吸引能减少;负离子间排斥能减少。     

COMPUTERIZED SIMULATION OF THERMODYNAMICS FOR MOLTEN LiF-KF SOLUTION BY MONTE CARLO METHOD

The structure and behaviour of LiF-KF solution,as a typical common-anion system,hasbeen simulated by Monte Carlo method.The calculation of partial radial distribution functionof ions,heat of mixing and potential energy distribution shows that the average distance be-tween Li~+ and F~- ions will significantly narrow after mixing of molten LiF and KF.This isvery similar to the lean-on-one-side effect in molten LiF-KCl solution.The calculated heatof mixing is in fair agreement with the measured one.The dominant source of the energy ofmixing may be that the decrease of the repulsion energy between cations,the decrease of theattraction energy between cations and anions,and the decrease of the repulsion energy be-tween anions.     

MOLECULAR DYNAMICS STUDY OF STRUCTURE IN MOLTEN SALT SOLUTION NaF-CaF_2

The NaF-CaF_2 system has been studied by molecular dynamics simulation.The paircorrelation functions between cations and anions and the bond angle distributions ofcation and anion triplets have been obtained.The bridging and complexing in the systemare discussed based on the pair correlation functions and bond angle distributions.Theresults simulated show that the F~- ions around a Ca~(2+)ion do not form tetrahedroncoordination,so some of small complexing clusters such as CaF_4~(2-)are hardly found.Apossible structure of F~- ions around Ca~(2+)ions is that three Ca~(2+)ions constitute anequilateral triangle through three Ca-F-Ca bridges and two F~- ions are located overand under the center of the right triangle,respectively.Meanwhile,on the outside of thetriangle,every Ca~(2+)ion has other two F~- ions as its neighbors.     

MOLECULAR DYNAMIC SIMULATIONS OF MOLTEN NaF

The structure and transport properties in molten NaF have been studied using the method ofmolecular dynamics simulation. The calculations are based on two models of interionic potentials,which are Fumi-Tosi potential (FT) and the Fumi-Tosi potential without Van derWaals attractive item (FT). The radial distribution function (RDF) and the Na~+ andF~- self-diffusion coefficients have been calculated. The calculated results are in good agreementwith the experimental ones. The calculation shows that the two models give nearly identicalradial distribution function and self-diffusion coefficient, but the results of FTpotentialare a little better than those of FT potential.     

REACTION PROBABILITIES OF ENERGETIC SPECIES AT GROWING DIAMOND FILM SURFACES BY MOLECULAR DYNAMICS SIMULATION

A Molecular Dynamics (MD) simulation with Tersoff empirical many-body potential has been employed to investigate the growth processes of diamond film with energetic species deposition. In the present study, we have studied the reaction probabilities of energetic species with energies of 0.1eV to 10eV at the substrate temperature of 1100K. In the cases of the diamond growth on the surface with H passivation, the reaction probability of hydrocarbon species considerably increases when the species energy is higher than 2eV. This means that the diamond film can grow in the case of high incident species energy without the process of hydrogen abstraction, which is needed in the case of incident species with low energy. The reaction mechanism of energetic species on hydrogen passivated diamond surface is also discussed.