Why do some compounds absorb radiation in the visible range?
A. Because the amount of energy of each photon corresponds to the HOMOLUMO gap for those compounds.
B. Because the amount of energy of each photon corresponds to a vibrational excitation of the molecule.
C. Because the amount of energy of each photon corresponds to the activation energy of those compounds reacting.
D. Because the amount of energy of each photon corresponds to the energy needed to increase the temperature of the molecule.
