Ab initio calculation by Gaussian

《Ab initio calculation by Gaussian》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。

1、AbinitiocalculationbyGaussianNov2005groupmeetingResources•ForesmanandFrisch,ExploringChemistrywithElectronicStructureMethods,Chapter3,4•GaussianUser’sReference•TechnicalsupportinformationofGaussian.com•ModernQuantumChemistry•AbInitioMolecularOrbitalTheroyGaussian98C

2、apability•Molecularenergiesandstructures•Energiesandstructuresoftransitionstates•Bondandreactionenergies•Molecularorbitals•Multipolemoments•Atomicchargesandelectrostaticpotentials•Vibrationalfrequencies•IRandRamanspectra•NMRproperties•Polarizabilitiesandhyperpolariz

3、abilities•Thermochemicalproperties•ReactioinpathwaysExecutingaGaussianjob•SettingupGaussianenvironment•Preparinganinputfile•Runningtheprogram,(batchprocessing)•ExamineandinterpretingtheoutputOverviewofaGaussianInputInputSectionContentsLink0CommandsScratchfilesandjob

4、resourcelimits*RouteSectionJobtypeandmodelchemistry*blanklineSeparation*TitleSectionDescribesthejobfortheoutputandarchive*blankline*MoleculeSpecificationGivethestructureofthemolecule*blanklineVariablesSectionSpecifiesvaluesforthevariablesusedintheblanklinemoleculesp

5、ecificationExampleforFrequencyCalculationUsingZ-Matrix#TRHF/6-31G(d)OPTFREQtestH2C1N3HCNHFfrequencycalculation01CResultsυCNStretchυCHStretchBendH1AB(cm-1)(cm-1)(cm-1)N1AN2HABCalculated*24383679889AB1.079(Harmonic)AN1.165Experiment20963311713HAB179.9*BeforeScalingFre

6、quencyCalculation•OptimizetoaStationaryPoint•Calculatethesecondderivativeofenergyinacertainmethodandbasissetwithrespecttoatomicposition•MassweighttheHessiananddiagonalize•Determinetheprincipalaxesofinertia•Generatecoordinatesintherotatingandtranslatingframe•Transfor

7、mtheHessiantointernalcoordinatesanddiagonalize•CalculatethefrequenciesFeaturesofPotentialEnergySurface(PES)GeometryOptimization•Featuresofenergysurface•Energyderivatives•OptionsforoptimizingequilibriumgeometriesOpt=(MaxCycle=N,StepSize=N)•Optionsforoptimizingtransit

8、ionstatesOpt=TS,Opt=QST2,Opt=QST3,Opt=(path=M)•OptionsforReactionpathfollowingIRC=Forward,IRC=(Maxpoints=N,StepSize=N)Energyderivatives•An