Next: Relation of Einstein's Coefficients
Up: Einstein's Coefficients
Previous: Induced Emission
Beside radiative processes, energy states of atoms are changed
by collisions with other atoms and molecules, which are called
collisional excitation and deexcitation.
Since such transitions are proportional to the density of atoms or molecules,
the number of transitions is written as follows:
for excitation from n to n
and deexcitation from n to n
where the coefficients are determined by laboratory experiments and
quantum mechanics calculations.