晶体学结构的解析-X-ray粉末衍射法Topas软件教学提纲

晶体学结构的解析X-ray粉末衍射法Topas软件李国宝北京大学化学学院2006晶体学结构晶体学结构•一种描述•简单原则三斜•合理原则讨论内容•基本处理(结构解析(一))•结构解析(二)•结构精修•一般性问题结构解析(一):基本处理•样品的准备和数据的采集•数据的处理(衍射图)一般步骤•数据的读入•寻峰(峰形拟合)•指标化•空间群的判断•结构解析数据的读入•布鲁克衍射仪的数据(*.raw)•理学衍射仪的数据•中子衍射的数据程序的启用可读入数据的格式•布鲁克衍射仪的数据(*.raw)BrukerAXSbinaries(DIFFRACATandDIFFRACplus)•*.DATSeveralASCIIfileformatsincludingLHPM/RIET7/CSRIET,GSAS(std-const,alt-ralf)andFullProf.•*.XDD/*.CALASCIIfileformat.*.XY,*XYEASCIIfileformats.Canbeusedfornon-equidistantx-axissteps.岛津衍射仪的ASCII数据*Group:YSH*Data:Ti-c1*FileName:Ti-c1.RAW*Comment:10.00000.02000120.00202200238188236210210208220198218224198192210190210222192218196186196216186*Group:YSH*Data:Ti-c1*FileName:Ti-c1.RAW*Comment:*550110.00000.02000202200238188236210210208220198218224198192210190210222192218理学衍射仪的ASCII数据GSAS数据格式5.0000.020120.0000501047.3.2006BANK15751575CONST500200STD137412941388136813421366135013641400136013601410137213381330130813181372137413141414134613401348134213181290131413841348129413161358128013361294137812681324137412761356132012801388130013961386128213061332133612821328129813741392135012621310*.XY格式050104OriginalData5751513725.0213845.0413705.0613885.0813845.113345.1213785.1413525.1613725.1813685.21378513725.0213845.0413705.0613885.0813845.113345.121378界面简介（userinterface）•MenubarContainsthenamesofsubmenus,whichprovidelistsofallcommandsavailabletogetherwiththeirshortcutsrespectivelytoolbaricons,ifexisting.•ToolbarDisplaysthemostimportantcommandsinformoficonsforfastaccess.•WorkingAreaContainsallelementsneededforprofilefittingsuchasobservedandcalculateddata,fitparameters,andfitresults,whicharedisplayedinseparatedviews.•StatusBarDisplayssomecontextsensitivehelpinformationandthex-andy-coordinatesofthedatacursorintheactiveScanWindow,whichisdescribedinsection2.2.数据的处理数据的组成背底峰位置峰形Globalitem(全域项)•Background(section2.3.2.4)•Instrument(section2.3.2.5)•Corrections(section2.3.2.6)•Miscellaneous(section2.3.2.7)•Display•AllPeaks(section2.3.2.8)•AllStructures/hklPhases(section2.3.2.11)BackgroundTwobackgroundfunctionsareprovided1.aChebychevpolynomialofanyorder2.a1/Xfunction.TheChebychevCoefficientspagecontainsthecoefficientsofthepolynomial.Emissionprofile(光源的信息)GivestheabilitytoaddanddeleteemissionlineswhichformtheemissionprofileoftheX-raysource.TheOptionspagecontainsthefollowingoptions:Option:Remarks:•YminonYmaxDeterminesthex-axisextenttowhichpeaktailsarecalculated(cutoff)•NoThdependenceDefinesanemissionprofilethatis2θindependent.Allowstheuseofnon-X-raydataorfittingtonegative2θvalues.•ForLAMcursorSwitchesthemousecursortoamulti-linecursorrepresentingthedifferentemissionlinesofthecurrentemissionprofile(Fig.2-14)•LamforBraggangleOnlyforexpertusers,refertotheTechnicalReferencemanual•CalculateLamOnlyforexpertusers,refertotheTechnicalReferencemanual*.lam文件的内容普通衍射仪：lamymin_on_ymax0.0001la0.653817lo1.540596lh0.501844la0.346183lo1.544493lh0.626579布鲁克的D8Advance：lamymin_on_ymax0.0001la1lo1.540596lh0.401844Instrument（仪器参数）•Bragg-Brentanogeometry•AdditionalConvolutionsBragg-BrentanogeometryCorrectionsMiscellaneousFitmethodConstraintsandkeywords1)SPF:SinglepeakfittingNoconstraintsbydefault.Optionallyallprofileparameterscanbeconstrained(e.g.sameshape,samewidth,relativeintensity,...)Keywords:xo_I,d_IWPPF:WholePowderpatternfitting.•Noconstraintsbydefault.Optionallyallprofileparameterscanbeconstrained(e.g.sameshape,samewidth,relativeintensity,...)•Profileparametersconstrainedtobesmoothlyvaryingfunctionsof2θKeywords:xo_I,d_IWPPD:WholepowderpatterndecompositionPawleyandLeBailmethodNumberofpeaksandtheirpositionsconstrainedbycrystalsystem/spacegrouppluslatticeparametersKeyword:hkl_IRietveld:Rietveldstructurerefinement,ab-initiostructuredeterminationPeakintensitiesconstrainedbythecrystalstructureKeyword:str1)FordetailsrefertotheTechnicalReferencemanual寻峰单谱线拟合步骤峰形函数TopasUsersManual.pdfTOPAS提供的两类峰形拟合方法•1.AnalyticalProfileFitting:analyticalpeakshapefunctions(PSF)Gaussian,Lorentzian,sumsofGaussiansorLorentzians,Voigt,pseudo-VoigtandPearsonVIIfunctions•2.DirectConvolutionApproach:Y(2)=W⊗F1(2θ)⊗F2(2θ)⊗...⊗Fi(2θ)⊗...⊗Fn(2θ)Y(2θ)istheobservedlineprofileshape,Wisthesourceemissionprofile,and⊗denotestheconvolutionprocess.Sourceemissionprofiles（衍射源谱线的描述）单色器对峰形的影响DirectconvolutionapproachEmpiricalparameterisation（直接卷积法：实验参数法）经验函数Directconvolutionapproach:Fundamentalparameters（基本参数法）Diffractometerconfigurationsandtheirgeometricalaberrations•DivergentBeamLaboratoryDiffractometers•ParallelBeamDiffractometersDivergentBeamLaboratoryDiffractometersPositionsensitivedetectors(PSDs)ParallelBeamDiffractometersPositionsensitivedetectors(PSDs)Treatmentofsatellitepeaksandtubetails全谱拟合如何指标化•LSI•LP-SearchFolie.77©2001BrukerAXSAllRightsReservedAdvancesinIndexingofPowderDiffractionPatterns:IterativeUseofLeastSquares(LSI)andMonte-CarloBasedWholePowderPatternDecompositionArntKernFolie.78©2001BrukerAXSAllRightsReservedTOPASV3TOtalPatternAnalysisSolutionsIntensityExtractionLeBail,PawleyStructureDeterminationusingF2(obs)StructureRefinementusingyi(obs)ProfilingLeBail,PawleyStructureDeterminationANDRefinementu