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1、CoherentControlCoherentControlattemptstocontrolachemicalreactionwithlight,usuallyacleverlyshapedultrashortlaserpulse.Whyit’shard:IVR.Usingshapedpulsesand aniterativeapproach.Wave-functionPotentialC=catalystConventionalmethodsofchemicalcontrolMuchcanb
2、edone,butnoteverythingwe’dlike.IVRoccursonafew-fstimescale,solongpulsesexciteentiremolecule,andtheweakestbondbreaks,nomatterwhichbondwasexcited.ExciteonebondAfewfslater,however,theentiremoleculeisvibrating.IntramolecularVibrationalRedistributionThebo
3、ndvibratesSingle-parametercontrolSurprisingly,thesesimplemethodsoftenwork,buttheyarenotgeneral.Coherentcontrol:UsingshapedultrashortpulsestocontrolthereactionCananultrashortpulsecauseamoleculetovibrateinsuchawayastobreakthebondofourchoice?Thephysicso
4、fcoherentcontrolMoleculeE-fieldofLaserPerturbedSystemWave-functionPotentialThepulseelectricfieldperturbsthemoleculeandpotentiallydissociatesit.Thetrickistocomputetherequiredpulseelectricfield.Wave-functionPotentialTryingtodothetheoryforcoherentcontro
5、lHsystem=Hmolecule+Hradiation+HinteractionHradiationknownHmoleculesmallmolecules:approximatelargemolecules:unknownHinteractionweakfield:knownstrongfield:unknownFirst,weneedtoknowthecompleteHamiltonianforthemoleculeandradiation:Forallbutthesimplestmol
6、ecules,it’shopelesstosolvetheproblem.Wecouldtrytosolvetheproblemtheoretically,butit’seasiertojustdoititerativelyinthelab.Pulse-shapingisimportantforcoherentcontrol.GeneticalgorithmforcoherentcontrolThisalgorithmwasdevelopedforcomputeroptimization,but
7、,forcoherentcontrol,itcanbeimplementedaspartofanexperiment.Ageneticalgorithmcanminimizethepulselength.UsingalearningalgorithmtoperformcoherentcontrolCoherentcontrolofasimplegasphasereactionShapedPulseCO2CCl4CCl2OReactionunderstudyMurnaneandKapteyn,Un
8、iversityofColoradoH3CCH3COH3CCH3CO+++Coherentcontrolwithacetone(gasphase)LevisandcoworkersAcetonecanbebrokenintovariouspieces.Alaserpulsecouldhelp.25H3C-C-CH3+=20151050Normalizedionsignal6050403020100Mass,amuM-15+M-30+H2O+CH3+C+C++H+O2+(Acetone+)OMas
