| The dissociation or ionization of a water molecule in liquid water is amongst the most fundamental events in aqueous solution chemistry. Because of the ultrafast time scales (10--100 fs) involved, the dynamics have not been directly probed by experiment. There is much theoretical discussion on this issue, however, the mechanistic details remain rather controversial. Femtosecond spectroscopies provide a route to explore liquid water dynamics, however, typically to initiate such small molecule system requires ∼10 fs pulses in the "photochemical" ultraviolet (UV) region (<300 nm), a difficult spectral range for femtosecond sources. The development of ultrashort-pulse light sources in the short-wavelength region of the spectrum is therefore a matter of great importance. In this work we demonstrate the implementation of a unique femtosecond UV laser source for spectroscopy studies in the condensed phase currently with 20 fs time resolution. |
