How are chlorine atoms formed from chlorine molecules like short-lived free radicals?

Chlorine atoms are formed from chlorine molecules ($C{l}_2$) through a process of dissociation, typically initiated by ultraviolet irradiation.12

In this process, the absorption of electromagnetic radiation provides the energy necessary to break the covalent bond holding the two chlorine atoms together in the diatomic molecule. This can be represented by the following chain-initiation step:12

$$C{l}_2\to 2·Cl$$

Once formed, these chlorine atoms act as short-lived, highly reactive free radicals. Because they possess an unpaired electron, they are chemically unstable and seek to react with other species. While some chlorine atoms may recombine to reform $C{l}_2$ molecules, others participate in chain reactions, such as the synthesis of chloromethane from methane, where they are consumed and subsequently regenerated, allowing the reaction to proceed through multiple propagation steps.12