采用PCM模型计算溶液中的紫外吸收光谱ThePCMmethodinGaussian09includesanexternaliterationprocedurewherebytheprogramcomputestheenergyinsolutionbymakingthesolventreactionfieldself-consistentwiththesoluteelectrostaticpotential(thelatterbeinggeneratedfromthecomputedelectrondensitywiththespecifiedmodelchemistry).Step1:Groundstategeometryoptimizationandfrequencies(equilibriumsolvation平衡溶剂化：在电子结构不发生改变时，若分子几何结构发生变化则溶剂也跟着变化).ThisisastandardOptFreqcalculationonthegroundstateincludingPCMequilibriumsolvation.获得溶剂中基态稳定几何结构，默认为Eq状态%chk=01-ac#B3LYP/6-31+G(d,p)OptFreqSCRF=(Solvent=Ethanol)Acetaldehydegroundstate01分子说明(请自行补充)Hereistheenergyofthegroundstateoptimizedgeometryinsolution:SCFDone:E(RB3LYP)=-153.851761719A.U.after1cyclesStep2:Verticalexcitationwithlinearresponsesolvation.默认为Non-Eq过程ThisisaTD-DFTcalculationoftheverticalexcitation,thereforeatthegroundstateequilibriumgeometry,withthedefaultsolvation:linearresponse,non-equilibrium.Weperformasingle-pointTD-DFTcalculation,whichdefaultstonon-equilibriumsolvation.Theresultsofthisjobwillbeusedtoidentifywhichstateorstatesareofinterestandtheirordering.Theseresultsgiveareasonabledescriptionofthesolvationoftheexcitedstate,butnotquiteasgoodasthatfromastate-specificsolvationcalculation.Inthiscase,weseethatthen→π*state(产生第一激发态的跃迁方式)isthefirstexcitedstate.Next,wewillusethestate-specificmethodtoproduceabetterdescriptionoftheverticalexcitationstep.复制以上step1中的01-ac.chk,并将复制文件命名为02-ac.chk，然后执行如下操作计算紫外跃迁吸收光谱。下边这个计算默认为non-equilibriumsolvation。垂直激发默认为NonEq过程，但此时没有使用EI%chk=02-ac#B3LYP/6-31+G(d,p)TD=NStates=6SCRF=(Solvent=Ethanol)Geom=CheckGuess=ReadAcetaldehyde:linearresponseverticalexcitedstates01Theverticalexcitation(absorption)tofirstexcitedstatefromthenon-equilibriumsolvationlinearresponsecalculation:发生电子跃迁时，溶剂来不及运动，所以叫做non-equilibriumsolvationlinearresponseExcitedState1:Singlet-A"4.3767eV283.28nmf=0.0000=0.000Thus,thegroundstatetofirstexcitedstateabsorptionisat283.28nm,computedviathelinear-responseapproach.Step3:State-specificsolvationoftheverticalexcitation.Thiswillrequiretwojobsteps:firstthegroundstatecalculationisdone,specifyingNonEq=writeinthePCMinputsection,inordertostoretheinformationaboutnon-equilibriumsolvationbasedonthegroundstate(之前基态优化的时候是equilibriumsolvationlinearresponse情况下完成的，这里重新改用NonEq方法，并将信息保存下来).查得最后的能量数据为E(RB3LYP)=-153.851761719Second,theactualstate-specificcalculationisdone,readinginthenecessaryinformationfornon-equilibriumsolvationusingNonEq=read,andspecifyingthecheckpointfilefromStep2:这一步从step3的第一步中读取NonEq信息，并执行激发态计算，获得垂直激发的能量。查得最后的能量数据为E(RB3LYP)=-153.850869764。同时会给出AfterPCMcorrections,theenergyis-153.687679830a.u.由于设定了Root=1，所以只会给出第一激发态的如下详细信息：Thisstateforoptimizationand/orsecond-ordercorrection.Copyingtheexcitedstatedensityforthisstateasthe1-particleRhoCIdensity.但不知道这个信息有什么用处。最后给出的能量也许是第一激发态弛豫前的能量，而非基态能量.3.1与step1相同，区别在于采用NonEq=Write保留了环境状态作为下一步NonEq过程的状态3.2针对3.1的NonEq=Write环境，用NonEq=Read读取此环境。采用SCRF=EI方法使得溶质的第一激发态(Root=1指定为针对第一激发态)调整e...
