1、采用采用PCM模型計算溶液中的紫外吸收光譜模型計算溶液中的紫外吸收光譜ThePCMmethodinGaussian09includesanexternaliterationprocedurewherebytheprogramcomputestheenergyinsolutionbymakingthesolventreactionfieldselfconsistentwiththesoluteelectrostaticpotential(

2、thelatterbeinggeneratedfromthecomputedelectrondensitywiththespecifiedmodelchemistry).Step1:Groundstategeometryoptimizationfrequencies(equilibriumsolvation平衡溶劑化：在電子結(jié)構(gòu)不發(fā)生改變時，若分子幾何結(jié)構(gòu)發(fā)生變化則平衡溶劑化：在電子結(jié)構(gòu)不發(fā)生改變時，若分子幾何結(jié)構(gòu)發(fā)生變化則溶劑也跟著變

3、化溶劑也跟著變化).ThisisastardOptFreqcalculationonthegroundstateincludingPCMequilibriumsolvation.獲得溶劑中基態(tài)穩(wěn)定幾何結(jié)構(gòu)，默認為Eq狀態(tài)%chk=01ac#B3LYP631G(dp)OptFreqSCRF=(Solvent=Ethanol)Acetaldehydegroundstate01分子說明(請自行補充)Hereistheenergyofthegr

4、oundstateoptimizedgeometryinsolution:SCFDone:E(RB3LYP)=153.851761719A.U.after1cyclesStep2:Verticalexcitationwithlinearresponsesolvation.默認為NonEq過程ThisisaTDDFTcalculationoftheverticalexcitationtherefeatthegroundstateequil

5、ibriumgeometrywiththedefaultsolvation:linearresponsenonequilibrium.WeperfmasinglepointTDDFTcalculationwhichdefaultstononequilibriumsolvation.Theresultsofthisjobwillbeusedtoidentifywhichstatestatesareofinteresttheirdering

6、.Theseresultsgiveareasonabledeionofthesolvationoftheexcitedstatebutnotquiteasgoodasthatfromastatespecificsolvationcalculation.Inthiscaseweseethatthen→πstate(產(chǎn)生第一激發(fā)態(tài)的躍遷方式)isthefirstexcitedstate.Nextwewillusethestatespecif

7、icmethodtoproduceabetterdeionoftheverticalexcitationstep.復制以上step1中的01ac.chk并將復制文件命名為02ac.chk，然后執(zhí)行如下操作計算紫外躍遷吸收光譜。下邊這個計算默認為nonequilibriumsolvation。垂直激發(fā)默認為NonEq過程，但此時沒有使用EI%chk=02ac構(gòu)全同，沒有改變。3.2的能量減去3.1的能量即為帶有溶劑效應矯正后的紫外吸收光譜

8、。復制01ac.chk文件，并將復制后文件重新命名為03ac.chk。執(zhí)行如下計算%chk=03ac#B3LYP631G(dp)SCRF=(Solvent=EthanolRead)Geom=CheckGuess=ReadAcetaldehyde:preparefstatespecificnoneqsolvationbysavingthesolventreactionfieldfromthegroundstate01NonEq=write

9、link1%chk=03ac#PB3LYP631G(dp)SCRF=(Solvent=EthanolExternalIterationRead)Geom=CheckGuess=ReadTD(NStates=6Root=1)Acetaldehyde:readnoneqsolvationfromgroundstatecomputeenergyofthefirstexcitedwiththestatespecificmethod01NonEq

10、=readHereistheenergyoffirstexcitedstate—atthegroundstateoptimizedgeometry—fromthenonequilibriumsolvationstatespecificcalculation:AfterPCMcrectionstheenergyis153.687679826a.u.Subtractingthisenergyfromthegroundstateenergy(

11、fromstep1)givesthegroundstatetofirstexcitedstateabsptionincludingthestatespecificsolvationcrection:at277.69nm.計算溶劑中的激發(fā)吸收光譜！！ExternalIteration方法方法(EI方法方法)的大致含義是：不同于之前常用的標準方法(標準方法中計算溶劑效應時先采用SCF方法獲得初步結(jié)果，然后把溶劑效果當做微擾項疊加到體系中獲得

12、體系性質(zhì))，EI方法直接針對溶劑體系的MP2結(jié)果獲得溶劑效果，讓溶質(zhì)自洽于環(huán)境溶劑。問題，若在3.2中，去除SCRF=EI關(guān)鍵詞，則能量數(shù)值有多大變化，激發(fā)波長有多大變化？若能量數(shù)值和激發(fā)波長均不變，則表示對光譜結(jié)果數(shù)據(jù)沒有影響，這樣就不叫statespecificsolvationcrection了。所以我想應該是變化了。若變化了，一次只能使用ROOT=N計算第N個激發(fā)的具體波長，每次激發(fā)單獨計算，這樣很費事。但我們可以計算振動系數(shù)比