a) Molecular absorption
b) Nonradiative relaxation
a) Molecular absorption is a physical process in which light with certain wavelength is absorbed by a molecule, inducing the change in the molecule from ground state to excited states.
b) Nonradiative relaxation is a physical process associated with the transfer of small amounts of energy through molecular and atomic collisions that lead to the generation of heat energy, but not the emission of photons.
c) Fluorescence is the physical process associated with the emission of electromagnetic radiation, typically visible light, due to excitation of atoms in an excited state caused by the absorption of light or other electromagnetic radiation.