How does flash photolysis help scientists identify unstable radicals?

Flash photolysis is a powerful experimental technique used to identify short-lived, unstable free radicals that act as transient intermediates in chemical reactions.12

The process functions through a two-step sequence:
* Generation: A sample, such as a gas or liquid, is subjected to an intense, short-duration burst of light (lasting microseconds or milliseconds). This energy causes the photochemical decomposition of molecules, creating a momentary high concentration of reactive free radicals.12
* Identification: A second, less intense flash of light is then used to analyze the resulting mixture via spectrophotometry. This allows scientists to observe and identify the transient molecular fragments before they react further or disappear.132

By enabling the direct observation of these otherwise elusive species, flash photolysis serves as a vital tool for understanding the mechanisms of fast chemical reactions.1