Question

(10 points) Draw a molecular energy diagram of the ground electronic state (S) and the first excited state (Si) including some vibrational levels (V) in each electronic state. Show the following transitions on the diagram and briefly explain each transition (a) (b) @a resonant absorption fluorescence phosphorescence intersystem crossing non-radiative decay

Answer 1

De activation Coa) De excitation Electronicaly excitecd Stades: JABLONSKI diagnans Excitation hue 4- Onimolecctlar (Deactivasion)physical pnoces ground a bny neleasing electnonically excited stal Retuaning ( it's excem energy Called Decxcitasi on Deactivaution, it i Unimoleculal photo phyxical pnoc es, MW NHeat (3hamel) Thamalde cay fsonaadiative process Radiative decay o Radiation, MO De-Excitaion Ve Radiative deactivations thermall NonRaciative Returning t ezcited stode by emitio aenergy in the form Light, Returning cacited state by neleasing enengyin the fon Heat. phosphone Intersy sten croving (Is) Fluonescence Irternal conversion Vibrational Coscacte Cve) Acence 1luatnated by Jabalanuki diogpa0 All these processes best which s qnaphical presentatian electaanic enogy levels oith mltiplitieu Vibnational cascade vc) Deacthvation eruited stade b neleasing Heat eneagy lth louoering Vibnatianal levels im a particcdlor Electroniclevel S,Sa. S Heat vo Deactivation Ex stbeleaing enensy to heat, Change in meeltipiicis Intennal convenaion Cre) electronic level the orm

JABLONSKI Diag nan HeavyFne Radiative deachivaliars FJavy ine mm Nonnadiatve deactivations hus Here cncited state drops fnom higbea ekctr onic level to LoLoer etaintng in multiplicig clectronic levet Hear JC a loss c excited stades ith Inter System Cr04sing ( sc):Deczaitation Heat enegy and y Changing mpliciy Fonbiden /Delayecl process S, Vo Hear FLOORE SCENCE :- Retcorning Eae S Groard St yTeleasing enegy in the fom light ithou changa in medlipliciy It is allouoe d proces and acasonbly expected be Fast, S. Vo S.Vo So Vo CHOSDHORE SCENCERetuaring Exst ts gound At. stith emimion oith Change to multiplicg It's Fonki delen process/ Delayed proe nadi ation T.V2 () phosphonescen a

Reveye1sc, Ise chenical chang ISC 5 chenical Changa. Flaorescence TM C phoophavescence INTER SYSTEM CROSSING CTSC) MORT Imp ocess photochenical neactions. Fonbi deler process in 10 See 1 Sec , 2 Sec Highy ebbicke nt Lus eibici Modenaldy ebbic Toebbicient E ebticieney depends on Enugy gap b Singlet E it's conrespanlig Small energy gp Levels (SIT) nead ily ovealapps & TLe plet states. ebicient TSC. Carbonyl compa's h ehirap T Leves, Laage, then veny loo probabil5 ot averlapping Levels 3&T, inebticient in I (will not fnuolue in Isc) Ole tins ( T cnengy ga ba Singlet & ic's Conresponding Taiplet, intermediali Cnot toe amall not Leste), Sloo ISC, Moderatdy tticient at ISC Arematic ydnocautbons, ( SI S Highelbicient SC Modenatedy e16icient 1sc 4 Aromatic Hiydo cealen Ineicim de bins 4* 13 Butadiene 1242 KC Pe 64.1 K Cal fModa Es = 124.2 KCallmale Eo KCal (Mab ET GOKCO IneHicient Isc
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