UV-induced dynamics at extreme time scales

Several important phenomena occuring in nature such as DNA damage and ozone photolysis are triggered by UV radiation, photoexciting the molecular system below the ionization threshold. Tracking the electronic processes in the neutral states of molecules with sufficient temporal resolution is now within reach thanks to our novel light source delivering few-femtosecond UV pulses (see FEW-FEMTOSECOND UV LIGHT SOURCES). In combination with near-infrared or extreme ultraviolet light pulses we perform time-resolved measurements to investigate a number of electron and nuclear dynamics in UV-excited molecules. Through the detection of charged particles, the information obtained notably allows us to disentangle and identify the molecular degrees of freedom at play to develop schemes that, for instance, can prevent the photofragmentation of small neutral molecules such as halogenated hydrocarbons and nucleobases within the first few femtoseconds following photoexcitation.

Reference: M. Galli et al., "Generation of deep ultraviolet sub-2-fs pulses", Opt. Lett., Vol. 44, Issue 6, pp. 1308-1311 (2019).