1. Einstein Coefficients
m
Harry Kroto 2004

2. Einstein Coefficients
m
Harry Kroto 2004

3. Einstein Coefficients
Bn←m
m
Harry Kroto 2004

4. Einstein Coefficients
Bn←m
m
Harry Kroto 2004

5. Einstein Coefficients
Bn←m
Bn→m
m
Harry Kroto 2004

6. Einstein Coefficients
Bn←m
Bn→m
m
Harry Kroto 2004

7. Einstein Coefficients
Bn←m
Bn→m
An→m
m
Harry Kroto 2004

8. Einstein Coefficients
Bn←m
Bn→m
An→m
m
A = 1.2 x 3 n em2 transitions per sec
Harry Kroto 2004

9. Einstein Coefficients
Bn←m
Bn→m
An→m
m
A = 1.2 x 3 n em2 transitions per sec
Spontaneous emission lifetime 
Harry Kroto 2004

10. Einstein Coefficients
Bn←m
Bn→m
An→m
m
A = 1.2 x 3 n em2 transitions per sec
Spontaneous emission lifetime 
 (sec) = 1/A = 1037/3 sec
Harry Kroto 2004

11. Lifetime (secs)
 ~ 1037/3
Harry Kroto 2004

12. e = 1Debye 1yr = 3 x 107 sec * magnetic dipole
  (Hz) 3 (Hz3)  (sec)
H (1420 MHz) cm 1.5x x *
H2CO rotations cm 3 x x
CO2 vibrations  3 x x
Na D electronic nm 1.5 x x
H Lyman  nm 3 x x
e = 1Debye yr = 3 x 107 sec * magnetic dipole
Harry Kroto 2004

13. e = 1Debye 1yr = 3 x 107 sec * magnetic dipole
  (Hz) 3 (Hz3)  (sec)
H (1420 MHz) cm 1.5x x *
H2CO rotations cm 3 x x
CO2 vibrations  3 x x
Na D electronic nm 1.5 x x
H Lyman  nm 3 x x
e = 1Debye yr = 3 x 107 sec * magnetic dipole
Harry Kroto 2004

14. e = 1Debye 1yr = 3 x 107 sec * magnetic dipole
  (Hz) 3 (Hz3)  (sec)
H (1420 MHz) cm 1.5x x *
H2CO rotations cm 3 x x
CO2 vibrations  3 x x
Na D electronic nm 1.5 x x
H Lyman  nm 3 x x
e = 1Debye yr = 3 x 107 sec * magnetic dipole
Harry Kroto 2004

15. e = 1Debye 1yr = 3 x 107 sec * magnetic dipole
  (Hz) 3 (Hz3)  (sec)
H (1420 MHz) cm 1.5x x *
H2CO rotations cm 3 x x
CO2 vibrations  3 x x
Na D electronic nm 1.5 x x
H Lyman  nm 3 x x
e = 1Debye yr = 3 x 107 sec * magnetic dipole
Harry Kroto 2004

16. e = 1Debye 1yr = 3 x 107 sec * magnetic dipole
  (Hz) 3 (Hz3)  (sec)
H (1420 MHz) cm 1.5x x *
H2CO rotations cm 3 x x
CO2 vibrations  3 x x
Na D electronic nm 1.5 x x
H Lyman  nm 3 x x
e = 1Debye yr = 3 x 107 sec * magnetic dipole
Harry Kroto 2004

17. e = 1Debye 1yr = 3 x 107 sec * magnetic dipole
  (Hz) 3 (Hz3)  (sec)
H (1420 MHz) cm 1.5x x *
H2CO rotations cm 3 x x
CO2 vibrations  3 x x
Na D electronic nm 1.5 x x
H Lyman  nm 3 x x
e = 1Debye yr = 3 x 107 sec * magnetic dipole
Harry Kroto 2004

18. Collisions in the Interstellar Medium ISM
In space the pressures are low
Very low
If n = number of molecules per cc (mainly H) then
Harry Kroto 2004

19. Collisions in the Interstellar Medium ISM
In space the pressures are low
Very low
If n = number of molecules per cc (mainly H) then
2b = 103/n yrs per collision
Harry Kroto 2004

20. Collisions in the Interstellar Medium ISM
In space the pressures are low
Very low
If n = number of molecules per cc (mainly H) then
2b = 103/n yrs per collision
3b = 1023/n2 yrs per collision
Harry Kroto 2004

21. Collisions in the Interstellar Medium ISM
In space the pressures are low
Very low
If n = number of molecules per cc (mainly H) then
2b = 103/n yrs per collision
3b = 1023/n2 yrs per collision
Number densities are anything from
n =
Harry Kroto 2004

22. Harry Kroto 2004