CHGCAR--vasp手册

CHGCAR£leThis£lecontainsthelatticevectors,atomiccoordinates,thetotalchargedensitymultipliedbythevolume(r)¤Vcellonthe£neFFT-grid(NG(X,Y,Z)F),andthePAWone-centeroccupancies.CHGCARcanbeusedtorestartVASPfromanexistingchargedensity,forvisualisationtheCHG£leshouldbeused,sincethePAW-onecentreoccupanciesaredif£culttoparse.ItispossibletoavoidthattheCHGCARiswrittenbysettingLCHARG=.FALSE.intheINCAR£le(seesection7.45).InVASP,thedensityiswrittenusingthefollowingcommandsinFortran:WRITE(IU,FORM)(((C(NX,NY,NZ),NX=1,NGXC),NY=1,NGYZ),NZ=1,NGZC)Thexindexisthefastestindex,andthezindextheslowestindex.The£lecanbereadformat-free,becauseatleastinnewversions,itisguaranteedthatspacesseparateeachnumber.Pleasedonotforgettodividebythevolumebeforevisualizingthe£le!Forspinpolarizedcalculations,twosetsofdatacanbefoundintheCHGCAR£le.The£rstsetcontainsthetotalchargedensity(spinupplusspindown),thesecondonethemagnetizationdensity(spinupminusspindown).FornoncollinearcalculationstheCHGCAR£lecontainsthetotalchargedensityandthemagnetisationdensityinthex,yandzdirectioninthisorder.Fordynamicsimulation(IBRION=0),thechargedensityonthe£leisthepredictedchargedensityforthenextstep:i.e.itiscompatiblewithCONTCAR,butincompatiblewiththelastpositionsintheOUTCAR£le.ThisallowstheCHGCARandtheCONTCAR£letobeusedconsistentlyforamoleculardynamicscontinuationjob.Forstaticcalculationsandrelaxations(IBRION=-1,1,2)thewrittenchargedensityistheselfconsistentchargedensityforthelaststepandmightbeusede.g.foraccurateband-structurecalculations(seesection10.3).Mind:Sincethechargedensitywrittentothe£leCHGCARisnottheselfconsistentchargedensityforthepositionsontheCONTCAR£le,donotperformabandstructurecalculation(ICHARG=11)directlyafteradynamicsimulation(IBRION=0)(seesection10.3).Banddecomposedchargedensity(parameters)分波电荷密度计算VASPcancalculatethepartial(banddecomposed)chargedensity部分（分波）电荷密度accordingtoparametersspecifiedinthefileINCAR.Itmustbenoted,thatthedensitiescalculatedbyVASP(includingthebanddecomposedchargedensity)arealwayssymmetrized对称的usingthespacegroup空间群andpointgroupsymmetrydeterminedbyVASP.根据设置INCAR中的参数，VASP可以计算分波电荷密度，算分波电荷密度通常考虑空间群和点群对称性。Insomecases(calculationofchargefromselectedk-points)thiscanleadtoundesiredresultsforthebanddecomposedchargedensity.Inthiscase,thesymmetryneedstobeswitchedoffforthegroundstateandsuccessivebanddecomposedchargedensitycalculations.有些情况，计算某些特定K点的电荷密度，可能得到的结果不是很理想。在这种情况下，关掉对称性，会得到比较理想的结果。MindthatthepartialchargedensitycanbecalculatedonlyifapreconvergedWAVECARfileexists,VASPenterstheevaluation评估routine程序veryquicklyandstopsimmediately立刻afterevaluatingthepartialchargedensity.Thisimplementation执行waschosentoallowafast快速的(almostinteractive交互、互动)recalculation重新计算ofthechargedensityforparticularbandsandkpoints.注意，计算分波电荷密度必须要有一个提前收敛的WAVECAR存在，VASP会快速评估这个分波电荷密度，然后很快地重新计算部分能点或者K点的电荷密度。ThefollowingparameterscontrolthebehaviorofVASP.以下参数控制VASP的行为LPARD:Evaluate评估、计算、求值partial(bandand/ork-point)decomposedchargedensity.Wewanttostress强调again,thattheorbitalsreadfromWAVECARmustbeconverged收敛inaseparate独立的、分开的prior预先run.IfonlyLPARDisset(andnoneofthetagsdiscussedbelow),thetotalchargedensityisevaluatedfromtheorbitalsandwrittentoCHGCAR.LPARD:计算分波电荷密度，必须有一个提前计算好的WAVECAR存在。如果，仅仅设置LPARD，计算总的电荷密度图。Thereareseveralwayshowtospecifyforwhichbandsthechargedensityisevaluated:IngeneraltheinputlineswithIBAND,EINTandNBMODcontrolthisrespectoftheroutine:有几种方式去指定那些能带的电荷密度需要算：一般输入IBAND,EINT和NBMOD控制程序IBAND:CalculatethepartialchargedensityforallbandsspecifiedinthearrayIBAND.IfIBANDisspecifiedintheINCARfileandNBMODisnotgiven,NBMODissetautomatically自动地tothesizeofthearray.IfIBANDisforinstance例如IBAND=20212223thechargedensitywillbecalculatedforbands20to23.IBAND:计算IBAND数列中指定的所有能带的分波电荷密度。如果，没有给定数组的大小NBMOD，那么NBMOD会根据IBAND的数组自动给定。如：IBAND=20212223，将计算20~23的分波电荷密度EINT:Specifiestheenergyrange能量区间ofthebandsthatareusedfortheevaluationofthepartialchargedensity部分电荷密度.Tworealvaluesshouldbegiven,ifonlyonevalueisspecified,thesecondoneissettoEf.IfEINTisgivenandNBMODisnotspecified,NBMODissetautomaticallyto-2.EINT:指定带的能量区间来计算分波电荷密度图。必须给定两个实数值，如果，仅仅给定一个值，第二个值设定为Ef。如果EINT给定了，NBMOD没有给定，那么NBMOD自动设定为-2.NBMOD:Thisinteger整数variable变量cantakethefollowingvalues0Numberofvaluesinthearray数列IBAND.IfIBANDisspecified指定,NBMODissetautomatically自动地tothecorrectvalue准确值(inthatcaseNBMODshouldnotbesetmanually手动intheINCARfile)0Takeallbandstocalculatethechargedensity,evenunoccupied未占据bandsaretakenintoaccount.0计算所有能带的电荷密度，包括未占据的能带，也要考虑-1Calculatethetotalchargedensityasusual.Thisisthedefaultvalueifnothingelseisgiven.-1像往常一样计算总电荷密度。这是什么都没有给定情况下的默认值。-2Calculatethepartialchargedensityforelectronswiththereeigenvalues特征值intherangespecified指定byEINT.-2计算由EINT指定范围中有本质值电子的分波电荷密度-3Thesameasbefore,buttheenergyrangeisgivenvs.theFermienergy.-3与-2一样，不过能量区间是给定的和费米能KPUSE:Specifieswhichk-pointsareusedintheevaluation计算ofthepartialdos.KPUSEisanarrayofintegervalues.KPUSE:计算指定K点值的分波电荷密度KPUSE=1234meansthatthechargedensityisevaluatedandsummedfor总结为thefirstfourk-points.Becareful:VASPchangesthekpointweightsifKPUSEisspecified.LSEPB:Specifieswhetherth