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,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,“,”,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,Femtosecond Time-Resolved Photoelectron Spectroscopy,Femtosecond Time-Resolved Phot,Outline,Introduction of femtosecond TRPES,Experimental methods of TRPES,Development of TRPES,Applications of femtosecond TRPES,Future directions,OutlineIntroduction of femtose,Why do we research femtosecond chemistry?,Chemical bonds form and break,on the femtosecond time scale,and on this time scale of time we can freeze the transition states at configurations never seen before.,Even if there is no reactants-to-products,transformation-physical change-one,is observing the most elementary of all molecular process.,Introduction,A.H.Zewail was awarded the Nobel,prize in chemistry in 1999.,“Femtochemistry has fundamentally,changed our view of chemical reac-,tions.”,Zewail,A.H.,J.Phys.Chem,.A,2000,104,5660,Zewail,A.H.et al,Nature,1992,355,66.,Why do we research femtoseco,Why do we research femtosecond TRPES?,laser-induced fluorescence,resonant multiphoton ionization,a small region of the reaction coordinate,resonant with an electronic transition,how?,photoelectron spectroscopy,Why do we research femtoseco,1.1 General aspects of femtosecond TRPES,The pump pulse is over,the wave packet,(,t),given by eq 1,1.1 General aspects of femtose,1.2 Photoelectron angular distribution(PADs),Within the molecular frame,the symmetries of the outgo-,ing electron partial waves are likewise related to the sym-,metry of the electronic state undergoing ionization.This,can be written as:,ex,+,e-,TS,ex,:the symmetry species of the prepared excited state,:the dipole operator,+,:the ion state,e-,:the symmetry species of the outgoing electron,TS,:the totally symmetric species,1.2 Photoelectron angular dist,2.1,How to complete femtosecond TRPES?,femtosecond pump-probe pulse!,Experiment,2.1 How to complete femtosec,2.2,Schematic of femtosecond laser,2.2 Schematic of femtosecond l,2.3 the detector of Photoelectron spectroscopy,Magnetic bottle time-of-flight spectrometer,Adv.:high collection efficiency,simple,rapid data readout,straightforward photoelectron-photoion coincidence meas-,urements(PEPICO),Disadv.:no angular distributions,low resolution,2D photoelectron imaging techniques(velocity-map imaging),Adv.:electron kinetic energy distributions,angular distributions,Disadv.:image reconstruction,coincident pump and probe laser reference frames,3D imaging techniques,!,2.3 the detector of Photoelect,2.4,Photoelectron-photoion coincidence methods,“Magic bottle”electron spectrometer:,photoelectron time-of-flight,Collinear time-of-flight mass spectrometer:,the mass of parent ion,Time-resolved PEPICO:,photoelectron and photoion kinetic energy distribution,Angle-resolved PEPICO:,photoelectron and photoion angular distribution,Stert,V.;Radloff,W.;,et al,Europhys.Lett.,1997,40,515.,Garner,M.C.,Hanold,K.A.;,et al,J.Phys.Chem,.A,1997,101,6577.,2.4 Photoelectron-photoion coi,3.,Development of TRPES,ns and ps TRPES:gas-phase,ps TRPES:intramolcular vibration relaxation,ps TRPES:reaction and solvation dynamics within,clusters,fs TRPES:,non-adiabatic dynamics of polyatomic molecules,anion photodissociation and wave packet dynamics,metal cluster anions and neutral clusters dynamics,photodissociation dynamics of polyatomic molecules,photoelectron-photoion coincidence detection technique,photoelectron angular distributions,Development,3.Development of TRPES ns a,FIG.1.A picture of polyatomic nonadiabatic dynamics.The a state prepared,by the pump laser decays into the lower lying bstate due to nonadiabatic,coupling.Here we assume that for these two states the Koopmans-,type correlations upon ionization are,complementary,:The a state,preferentially ionizes into the a1 ground state ion continuum,whereas the b,state preferentially ionizes into the b1 ion continuum,here shown as a,cation excited state.This scheme should allow the disentangling of electronic,from vibrational dynamics during nonadiabatic processes,as discussed,in the text.,4.1 Non-adiabatic intramolecular dynamics,Blanchet,V.;Zgierski,M.Z.,J.Chem.Phys.,2001,114,1194.,.,Application,FIG.1.A picture of polyatomi,4.2 Photodissociation dynamics of NO,2,Davies,J.A.;Leclaire,J.E;Continetti,R.E.,J.Chem.Phy,.,1999,111,1.,Davies,J.A.;Continetti,R.E.;Chandler,D.W.,Phys.Rev.Lett,.,2000,84,5983.,4.2 Photodissociation dynamics,4.3 Electron solvation in finite systems:,femtosecond dynamics of iodide,(water),n,anion clusters,Lehr,L.;Zanni,M.T.;Frischkorn,C.,Science,1999,284,635.,4.3 Electron solvation in fini,Development in detector technologies,Development of multiply photoelectron-photofr-agment coincidence and coincidence-imaging methods,Devlopment of high average power femtosecond VUV/XUV source and the attosecond laser source,Future directions,Development in detecto
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