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Absorption
Photon with energy is absorbed by the atom in the
state of n.
At the same time the atom is excited from the state n to n.
The number of this transition is proportional to the number of
atoms in the state n, , the number of photons passing and
a cross-section of this absorption.
This is written as
|
(2.135) |
where represents the average specific intensity of radiation with
corresponding wavelength.
This coefficient is called Einstein's coefficient for absorption.
Kohji Tomisaka
2007-07-08