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1、#BigcolloidparticlesandsmallLJparticlesunitsljThiscommandsetsthestyleofunitsusedforasimulation.Itdeterminestheunitsofallquantitiesspecifiedintheinputscriptanddatafile,aswellasquantitiesoutputtothescreen,logfile,anddumpfiles.Typically,thiscommandisusedattheverybe
2、ginningofaninputscript.这个指令设定模拟的格式，它决定了在输入脚本文件和数据文件以及在屏幕上显示的输出物，日志文件和垃圾文件中所有的单元格式。典型的是，它经常用于输入脚本的开头Forstylelj,allquantitiesareunitless.Withoutlossofgenerality,LAMMPSsetsthefundamentalquantitiesmass,sigma,epsilon,andtheBoltzmannconstant=1.Themasses,distances,ener
3、giesyouspecifyaremultiplesofthesefundamentalvalues.Theformulasrelatingthereducedorunitlessquantity(withanasterisk)tothesamequantitywithunitsisalsogiven.Thusyoucanusethemass&sigma&epsilonvaluesforaspecificmaterialandconverttheresultsfromaunitlessLJsimulationintop
4、hysicalquantities.对于lj格式，所有数量都是无量纲的。不失一般性的，lammps设定了基本量质量sigmaepsilon和波尔兹曼常数=1。你定义的质量，距离，能量是这些基本值的倍数。公式把衰减量或者是无量纲量（用*）和单元给出的相同的量关联起来。因此你可以用mass，sigma，epsilon值表示一个具体材料并且改变一个无量纲lj模拟的物理量的结果。mass=massormdistance=sigma,wherex*=x/sigmatime=tau,wheretau=t*=t(epsilon/m/
5、sigma^2)^1/2energy=epsilon,whereE*=E/epsilonvelocity=sigma/tau,wherev*=vtau/sigmaforce=epsilon/sigma,wheref*=fsigma/epsilontorque=epsilon,wheret*=t/epsilontemperature=reducedLJtemperature,whereT*=TKb/epsilonpressure=reducedLJpressure,whereP*=Psigma^3/epsilondyna
6、micviscosity=reducedLJviscosity,whereeta*=etasigma^3/epsilon/taucharge=reducedLJcharge,whereq*=q/(4piperm0sigmaepsilon)^1/2dipole=reducedLJdipole,momentwhere*mu=mu/(4piperm0sigma^3epsilon)^1/2electricfield=force/charge,whereE*=E(4piperm0sigmaepsilon)^1/2sigma/ep
7、silondensity=mass/volume,whererho*=rhosigma^dimatom_styleatomic原子类型atomic（原子的)Definewhatstyleofatomstouseinasimulation.Thisdetermineswhatattributesareassociatedwiththeatoms.Thiscommandmustbeusedbeforeasimulationissetupviaaread_data,read_restart,orcreate_boxcomma
8、nd.定义在模拟中用到的原子类型，这个决定了与原子有关的属性，这个命令必须用在模拟被设定之前通过read_data,read_restart,orcreate_boxAtomiconlythedefaultvaluescoarse-grainliquids,solids,metalsAtomic附加属性是只是默认值用于粗粒液体，固
