I'm working on a research project involving absorption spectra of particulates in solution. I was curious if someone could clarify or direct me to a resource that explains broadening mechanisms specifically for absorption spectra. For example, the oft-cited Heisenberg and Doppler broadening effects both make sense to me in the context of emission spectra, but I don't see the mechanism by which they would be influential in absorption spectra. But I also can't find a source to verify this, since emission and absorption spectra are often lumped together in the familiar statement "the absorption spectrum is simply the inverse of the emission spectrum"
Thanks very much for any advice.
Best Answer
The reason the statement is made
is because broadening mechanisms depend on kinematics, and kinematics is reversible.
By this I mean that if an emitting atom because of its thermal kinetic energy emits a photon of energy which, instead of E, is E+delta(E), where the extra energy comes because of its motion, the same atom instead of absorbing E will absorb E+delta(E) again because of its motion when the photon hits it. Statistically the broadening curves will be the same.