2.  l 

3.  l 

4.  l 

5.  l  Io

6.  l  Io I

7. dx Io I

8. γ is the absorption coefficientdx Io I
γ is the absorption coefficient
dI = - γIx dx

9.  l  Io I
dI = - γIx dx
dI/Ix = - γdx

10. I = ∫I=Io 1/Ix dI = - γ ∫x=0 dx
 l  Io I
dI = - γIx dx
dI/Ix = - γdx I
x=l
I = ∫I=Io 1/Ix dI = - γ ∫x=0 dx

11. I = ∫I=Io 1/Ix dI = - γ ∫x=0 dx
 l  Io I
dI = - γIx dx
dI/Ix = - γdx I
x=l
I = ∫I=Io 1/Ix dI = - γ ∫x=0 dx
[loge I – loge Io] = -γl

12. I = ∫I=Io 1/Ix dI = - γ ∫x=0 dx
 l  Io I
dI = - γIx dx
dI/Ix = - γdx I
x=l
I = ∫I=Io 1/Ix dI = - γ ∫x=0 dx
[loge I – loge Io] = -γl
I/Io = e-γl

13. I = Ioe-γl

14. I = Ioe-γl
Beer’s Law

15.  = (4/3ħc)
Harry Kroto 2004

16.  = (4/3ħc) n em2 1
Harry Kroto 2004

17.  = (4/3ħc) n em2 
Harry Kroto 2004

18.  = (4/3ħc) n em2  (Nm-Nn) 1 2 3
Harry Kroto 2004

19.  = (4/3ħc) n em2  (Nm-Nn) (o-) 1 2 3 4
Harry Kroto 2004

20.  = (4/3ħc) n em2  (Nm-Nn) (o-) 1 2 3 4
Square of the transition moment n em2
Harry Kroto 2004

21. n em2 ≡ ∫ψn*μeψmdτNB
n em2 ≡ ∫ψn*μeψmdτ
Harry Kroto 2004

22.  = (4/3ħc) n em2  (Nm-Nn) (o-) 1 2 3 4
Square of the transition moment n em2
Frequency of the light 
Harry Kroto 2004

23.  = (4/3ħc) n em2  (Nm-Nn) (o-) 1 2 3 4
Square of the transition moment n em2
Frequency of the light 
Population difference (Nm- Nn)
Harry Kroto 2004

24.  = (4/3ħc) n em2  (Nm-Nn) (o-) 1 2 3 4
Square of the transition moment n em2
Frequency of the light 
Population difference (Nm- Nn)
Resonance factor - Dirac delta function (0) = 1
Harry Kroto 2004