jablonski diagram · atomic spectroscopy source spectrum effec
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INDICATE THE EXCITED AND GROUND SINGLET AND TRIPLET STATES. INDICATE THE FOLLOWING TRANSITIONS: ABSORPTION, FLUORESCENCE, PHOSPHORESCENCE, NONRADIATIVE DECAY, INTERNAL CONVERSION AND INTERSYSTEM CROSSING. LABEL THE TRANSITIONS PROBED BY AT LEAST 4 TYPES OF SPECTROSCOPY STUDIED IN CHEM 314.
JABLONSKIDIAGRAM
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ATOMICSPECTROSCOPY
SourcespectrumEffec<vebandwidth:~0.001nm
SampleAbsorp0onEffec<vebandwidth:0.002-0.005nm
SignalatdetectorSmallerduetoabsorp<oninflameandmonothroughput
Absorp<onlinesbroadenedby:- UncertaintyEffect- Dopplerbroadening- Pressurebroadening
LEARNINGCHECK1. Howareatomicandmolecularspectroscopydifferent?
2. DiagramanAtomicAbsorp0onSpectrophotometer
3. DiagramandexplainhowaHollowCathodeLampworks.
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ATOMICVSMOLECULARSPECTROSCOPY
300 400 500 600 700 8000.0
0.5
1.0
1.5
2.0
Abs
orba
nce
(arb
.)
wavelength (nm)
FLAMEATOMICABSORPTIONSCHEMATIC
Ebert monochromator
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ATOMICEMISSIONSPECTROSCOPY
Excitedstatepopula<on
ATOMICFLUORESCENCESPECTROSCOPY
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HOLLOWCATHODELAMP(HCL)
MOLECULARSPECTROSCOPYCH13-15
CHEM314
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• Differen<atebetweenatomicandmolecularspec.• Iden<fy,diagram,anddescribehowthefollowing
instrumentcomponentsfunc<on.Alsoknowwhythesecomponentsareused.Sources:Xearc,Deuteriumarc,tungstenfilament,LEDSamplecuve/es:plas<c,glass,quartz
• Label,diagram,describeeachofthefollowinginstruments:SinglebeamUV-VissingleelementdetectorSinglebeamUV-Vismul<-elementdetectorDoublebeamUV-Visin<meandspaceFluorimeter
OBJECTIVES
0.0 0.1 0.2 0.3 0.4 0.50.0
0.2
0.4
0.6
0.8
1.0
Abs
orba
nce
(arb
)
[Kool-aid]
A=1.9 [Kool-aid]r2=0.97
0.0 0.1 0.2 0.3 0.4 0.50.0
0.2
0.4
0.6
0.8
1.0
Abs
orba
nce
(arb
)
[Kool-aid]
A=ε b[Kool-aid]b=pathlength
y=mx+b
ε molarabsorb<vity
BEER’SLAW:THERELATIONSHIPBETWEENCONCENTRATIONANDABSORBANCE
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1. Solu<onfactors2. Non-monochroma<clight3. Notanalyzingatlmax4. Straylight5. Mismatchedcuveles6. Instrumentnoise
0.0 0.5 1.0 1.5 2.0 2.5 3.00.0
0.5
1.0
1.5
2.0
2.5
3.0
Abs
orba
nce
(arb
)
[Kool-aid]
SOURCESOFNONLINEARITYOFBEER’SLAW
BUILDINGASPECTROSCOPICINSTRUMENT
Components1. Stableradia<onsource
2.Wavelengthisola<on-monochromator3.Transparentsampleholder/op<cs4.Detector-PMT,photodiode,PDA5.Signalprocessing
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BUILDINGASPECTROSCOPICINSTRUMENT
Components1. Stableradia<onsourcedeuteriumarclamp,Tungstenfilament,LED,Xearclamp
2.Wavelengthisola<on-monochromator
3.Transparentsampleholder/op<csQuartz,glass,plas<c
4.Detector-PMT,photodiode,PDA5.Signalprocessing
Con<nuumsourceswithconstantoutputasafunc<onofwavelengthrequiredformolecularspectroscopy
SOURCES
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BLACKBODYRADIATION
hlps://docs.kde.org/stable/en/kdeedu/kstars/ai-blackbody.html
Wein’sDisplacementLaw λmax=maxoutputλT=temp(K)L=luminosityA=surfaceareaα=constant
TUNGSTENFILAMENT
Outputspectrumat2870K
100um
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DEUTERIUMARC
XEARCRange200-1000nm,peak500nm
www.wikipedia.comhlp://zeiss-campus.magnet.fsu.edu/ar<cles/lightsources/images/
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LIGHTEMITTINGDIODELightemiIngdiode(LED)
GaAlAs λmax=900nmGaAsP λmax=650nmGaP λmax=550nmGaN λmax=465nmInGaN λmax=450nm
WhiteLEDInGaNdiodeplusphosphorRange:400-800nm
www.greenprophet.comhlps://lasermom.files.wordpress.com/2012/04/ledspectrum.png
SEMICONDUCTORSBandgap(Eg)-EnergyofgapbetweenHOMOandLUMO
HOMO-highestoccupiedmolecularorbital
LUMO-lowestunoccupiedmolecularorbital
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PNJUNCTIONS
LightemiIngdiode(LED)
GaAlAs λmax=900nmGaAsP λmax=650nmGaP λmax=550nmGaN λmax=465nmInGaN λmax=450nm
WhiteLEDInGaNdiodeplusphosphorRange:400-800nm
LEDVSSILICONPHOTODIODE
LED-Source Photodiode-Detector
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WAVELENGTHSELECTION
MONOCHROMATORS1. Entranceslit-providesrectangularop<calimage2. Collima<nglensormirror-makeslightbeamsparallel3. Dispersiveelement-disperseslightintocomponent
wavelengths4. Focusingelement-reformsrectangularop<calimagefocused
onfocalplane5. Exitslit-onfocalplane,selectsdesiredbandwidth
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OPTICSANDSAMPLEHOLDERS
01234
190 490 790 1090
Absorban
ce
Wavelength(nm)
Quartz Plas<c
DETECTORSVacuumphototube
Photomul0pliertube(PMT)
Siliconphotodiode
Photodiodearray(PDA)
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MOLECULARSPECTROSCOPICINSTRUMENTS
UV-VisSpectrophotometersinglebeamdoublebeammul<channel
Fluorimeter
SINGLEBEAMUV-VIS
PHOTODIODEARRAYUV-VIS
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DOUBLEBEAMUV-VIS
Doublebeaminspace
Doublebeamin<me
FLUORIMETER
scan monoex monoem
Excita<on scan fixedEmission fixed scan
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REVIEW
WHATKINDOFINSTRUMENTISPICTURED?HOWDOYOUKNOW?
Ebert monochromator
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WHATKINDOFINSTRUMENTISPICTURED?HOWDOYOUKNOW?
WHATKINDOFINSTRUMENTISPICTURED?HOWDOYOUKNOW?
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WHATKINDOFINSTRUMENTISPICTURED?HOWDOYOUKNOW?
Excitedstatepopula<on
WHATKINDOFINSTRUMENTISPICTURED?HOWDOYOUKNOW?
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WHATKINDOFINSTRUMENTISPICTURED?HOWDOYOUKNOW?
WHATKINDOFINSTRUMENTISPICTURED?HOWDOYOUKNOW?
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WHATKINDOFINSTRUMENTISPICTURED?HOWDOYOUKNOW?
WHATKINDOFINSTRUMENTISPICTURED?HOWDOYOUKNOW?
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WHATKINDOFINSTRUMENTISPICTURED?HOWDOYOUKNOW?
BEER’SLAWDERIVTATION
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ASIMPLEABSORPTIONEXPERIMENT
T=transmissionP0=incidentpowerP=transmiledpowerA=absorbanceε=molarabsorp<vityb=pathlengthC=analyteconcentra<on
Beer’sLaw
DERIVATIONOFBEER’SLAWT=transmissionP0=incidentpowerP=transmiledpowerA=absorbanceε=molarabsorp<vityb=pathlengthC=analyteconcentra<on
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WRITINGAPROCEDURE
1. Descrip<veTitle2. Purpose3. Background4. Safety-printMSDS5. Sampleprepara0on6. Instrumentparameters7. Datatables-inlabnotebook8. Dataanalysis9. References10. Whatdoyouneed?11. Appendices
CONTRIBUTINGRESOURCESTOWEBSITE(5PTSEA)5ptseach-upto20ptsextracredit
Resources
1. Descrip0ve0tle-Whathaveyoufound? books,ebooks,websites,anything
2. Source-Wheretofindtheresource(cita<onorweblink)
3. Content-Describewhatisavailable(2-3sentences)
4. ReliabilityandUsefulness-youropinionaboutresourcereliabilityandhelpfulness
5. Who’sContribu0ng?Yournameorpseudonym
Contribu0onsareonlyacceptedbeforetheapplicablereportisdue
Submitviaemail
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LOOKINGAHEAD
Monday(Feb8)-MolecularSpectroscopy(Ch13-15),Wri0ngProcedures
Tuesday/Thursday(Feb9,11)-Experiment1Metals
DueThursday:AnnotatedFigures1,Experiment1
Monday(Feb15)-Vibra0onalSpectroscopy
Due:ProjectOverview
Tuesday/Thursday(Feb16,18)-Experiment2-Plas0cs
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WHATKINDOFUV-VISINSTRUMENTISPICTURED?HOWDOYOUKNOW?
WHATKINDOFUV-VISINSTRUMENTISPICTURED?HOWDOYOUKNOW?
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