The BeerBougerLambert Law and emax

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The Beer-Bouger-Lambert Law and emax
The Beers law At a given l the proportion of
light absorbed by a transparent medium is
independent of the intensity of the incident
light and is proportional to the number of
absorbing molecules through which the light
passes.

• I0 is the intensity of incident light
• I is the intensity of transmitted light
• k is the absorption coefficient
• l is the path length through the sample
• is molar extinction coefficient or molar
  absorptivity
• c is the concentration in mol/L
• So k 2.303 e c

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Changes of Absorption Maxima
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AOs being combined must have similar energy and
the same symmetry with respect to the
internuclear axis
In-phase overlap region of AOs bonding MO
Out-of-phase overlap region of AOs (nodal plane)
antibonding MO
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Linear Combination of AOs (LCAO)
E- (EA - b)/(1-S)
b resonance energy it becomes 0 if D EA is
big S overlap integral that typically is about
0.2
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g even (gerade) and u odd (ungerade) with
regard to inverion
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Penta-1,3-diene in heptane
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Absorption of alkenes
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Absorption of alkenes
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Absorption of isolated chromophores