Absolute photoabsorption cross-section measurement of the Kr2F excimer at 248 nm

The photoabsorption of Kr2F in the excited electronic state 42Γ has directly been measured at 248 nm observing its fluorescence suppression induced by KrF laser radiation. The suppression signals have been measured in the laser power density range from 10 to 90 MW/cm2. The analysis has led us to conclude the following: the upper state of the absorption process is a bound electronic state and the photoabsorption cross section is (1±0.2)×10−18 cm2 which is about 1/5 of the value assumed in the current kinetic model of the KrF laser medium.