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Various Spectra• UV-Vis - Excitation of π-electrons or n-electrons• IR-Bond Vibration - Electronic Cloud Oscillation• Fluorescence – Light Absorption moves electron from GS
to ES then light emission (different wavelength)
Energy Level Diagrams, Hydrogen
1 K
2
34
-13.6 eV
-3.40 eV
-1.51 eV
L
-0.85 eV
hc
n
Z
n
ZeVE
ab
2
2
2
2
6.13
Molecular Orbitals
• New Energy– Bonding
– Anti Bonding
• Hybridization• New Shapes to
Orbitals with hybridization
•• •
•1s 1s
Accuracy of Spectrometer
• Spectral Resolution
• (Bandwidth)
• Δλ= s dλ/ds
• Slit width = s
• Precision of prism/grating, dλ/ds
Benzene
Metal Complexation
• Metal with π-electron Complex in water solution
• Colored Solution– Different color than
organic alone
Reagent Excess/Metal Excess
• Two Component Analysis
• Principle Component Analysis
• (More than two)
Fluorescence• Light Absorbed, λo
• Electron from GS to Excited State
• Electron Cascades back to GS
• Light Emission – Different color, λ1
• I=Kε(λo)IoQ (λ1)• Q=quantum efficiency• K device constant• Quenching at High C, Q
Fluorescence
• I=Kε(λo)IoQ (λ1)
• Q=quantum efficiency
• K device constant• Quenching at High C,
– Q
– self absorption
• Fluorophore– Chelating agents for metals
X-ray Fluorescence
• Two Steps– Absorption of X-ray
• Elimination of electron for k or L shell
– Collapse of L or M shell electron to fill hole
• Light emission (x-ray)
Potential X-ray Emissions• From K shell hole
– K, K, K,
– Zeeman Effect - 1, 2, 3
• From L shell hole– L, L, L,
Note Nomenclature Error
Generation of X-rays
• High Voltage Electrons
• Electron Scattering
• Electron Absorption– X-ray photo
ionization
XRF Detectors
• Energy-dispersive XRF– Semiconductor
• Wavelength dispersive XRF– Scintilation Counter