Time-resolved fluorescence measurements of KrF emission produced by vacuum ultraviolet photolysis of KrF2 and Kr/F2 mixtures

Vacuum ultraviolet (VUV) light radiation was used to produce electronically excited KrF excimers (in D-, B- and C-states) by the photolysis of KrF2 and F2/Kr mixtures at various excitation wavelengths. The excited KrF photoproduct quantum yield was measured over the excitation wavelength range of 120 to 200 nm, and a quantum efficiency of 0.11 was estimated at the peak absorption wavelength of 159 nm for KrF2. The collision-free fluorescence lifetime of the B-X transition near 248 nm was determined to be 9.5 ± 0.6 ns when the KrF2 was excited with the 159 nm light. Near gas kinetic rate constants were measured for the quenching of KrF B-X emission by KrF2 and CO2. Using the threshold wavelength needed for the production of excited KrF photofragments, an upper bound for the bond dissociation energy of KrF2 was determined to be 1.03 ± 0.05 eV. (orig.)