Time-resolved and integrated fluorescence spectral of a capacitively coupled longitudinal KrF excimer laser were measured in the UV visible range. Similar investigations were also carried out with a transversally pumped commercial excimer laser with a standard KrF gas fill. Both lasers were found to have very different spectra. The longitudinal laser showed very strong excitation of rare gas ions. Such high ion densities are avoided in transversal discharges by keeping the discharge homogeneous. However, the longitudinal discharge is capacitively self-stabilized so that no breakdown occurs.