Energy dissipation in excited state
Molecules in the excited state are unstable, and energy is to be attenuated in various ways. The physical path for energy dissipation in the excited state is shown in the figure.
When the excited state molecule has an excitation energy greater than the dissociation energy of the chemical bond, the molecular fragment is dissociated, and the portion exceeding the dissociation energy of the chemical bond becomes the kinetic energy of the molecular fragment. Through the transfer of excitation energy between molecules, an excited ground state complex will be formed, and electron transfer and chemical reactions (such as addition and dehydrogenation reactions) will occur.