Chemical time scales In calculating UV/VIS spectra with computational procedures (say, TD-DFT), it is commonly assumed that the geometry of the ground-state is still valid also for the excited state due to the short time scale (I more or less took this statement from here).

So I asked myself, are there good references on time scales for chemical processes?
Some phenomena may be obviously faster than others, but others (say, two molecular excitations) may be not that obvious to compare.

I am looking for something simple, like a table (or tables) with examples.
According to the Franck-Condon principle which you are implicitly referring to, absorption is indeed very fast compared to all other processes.

If you are looking for time scales of photophysical processes, I can suggest you for example B. Valeur's book "Molecular Fluorescence: Principles and Applications", chapter 3 (Characteristics of fluorescence emission). You'll find this list of characteristic times:


absorption: $10^{-15}$ s
vibrational relaxation: $10^{-12} - 10^{-10}$ s
$\ce{S_1}$ lifetime (fluorescence): $10^{-10} - 10^{-7}$ s
intersystem crossing: $10^{-10} - 10^{-8}$ s
internal conversion: $10^{-11} - 10^{-9}$ s
$\ce{T_1}$ lifetime (phosphorescence): $10^{-6} - 1$ s


as well as examples of molecules with their photophysical data. 

For chemical processes, it depends on many things, such as concentration, diffusion rates... and you would need to precise your question (type of photochemical reaction, type of quenching, etc.).