oxybenzone, and sulisobenzone) are studied by using femto‐and nanosecond time‐
resolved spectroscopy. Upon excitation, the compounds undergo an ultrafast excited‐state
intramolecular proton transfer (ESIPT) reaction as the major energy‐wasting process and
the rate constant of this reaction is k= 2× 1012 s− 1. The ESIPT yields a keto conformer that
undergoes a fast, picosecond internal conversion decay. However, a photodegradative …