molecular activation

Molecular activation occurs when a molecule absorbs energy, often from radiation, entering an energy-rich state where it can undergo unusual chemical reactions. This activation can lead to an electronically excited state, achieved through photon absorption, charged particle impact, or charge transfer. A more extreme form of excitation is ionization, where an electron is ejected, creating a positive molecular ion. The minimum energy required for this is the ionization potential.1

In chemistry, activation energy is the minimum energy needed for atoms or molecules to react or undergo physical transport. This concept is crucial in understanding reaction rates and diffusion coefficients, often represented by the symbol (E_a). In condensed matter, special activated states like excitons and polarons can form due to the collective behavior of molecules.23