The role of optical transitions between ionic and Rydberg states in a KrF laser

The upper laser level of a KrF laser is treated as a cluster containing sev eral hundreds vibration-rotation energy levels of the electronic state B, w hich is mixed due to collisions with the close ionic state C. The KrF (C) s tate is depleted as a result of optical transitions to a higher Rydberg sta te. This model explains the experimental data on the picosecond dynamics of the light amplification. The possibility of using a KrF laser as an amplif ier of radiation with a wavelength of 120 nm is discussed.