### oscillator strength

**(f-value)**
(fraction expressing QM's contribution to the probability of absorption)

**Oscillator strength** (or **f-value**) is a fraction
expressing the contribution of quantum mechanics
to the probability that a particular atom absorbs a photon,
thereby increasing its state of excitation. Each transition
has a unique oscillator strength, e.g., that for
the Lyman alpha transition is 0.416.

**Absorption cross section** and absorption coefficient
are other methods of
characterizing the probability of absorption. They
incorporate the oscillator strengths of associated
with a medium's chemical constituency, as well as
the states of excitation, states of ionization,
etc.

(*physics,quantum mechanics*)
http://en.wikipedia.org/wiki/Oscillator_strength

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