Subject: How many variations of atom or molecule excitations by a photon are there?

Photons seem to be able to change the energy state of matter in a various ways.
For example, in a photodiode the photocurrent is produced by changing the energy
state of an electron. In a scattering process, the vibrational state of the
molecule or atom is changed via absorption of the photon leading to dissipative
absorption or elastic scattering where another photon of the same frequency is
released immediatedly after excitation. Not to forget non-elastic scattering,
where a photon of another frequency is released. 
So far I only found these two ways of energizing matter. Are there still other
mechanisms ? I also do not know whether the excitation of an atom is different
to the excitation of a molecule, so that is why I speak of only "two" different
mechanisms here.
Is there a good way to categorize all these different photon-absorption and
energy changing mechanisms ? When light penetrates matter, is there always a
mixture of all these different mechanisms ?
How do we mathematically separate and describe explicitly all these different
excitation mechanisms ?

Re: How many variations of atom or molecule excitations by a photon are there?