Electron-Impact Excitation out of the Metastable Levels of Krypton

We have measured the electron-impact excitation cross sections out of the two metastable levels of Kr into the ten levels of the 4p(5)5p configuration. For a common 4p(5)5p final level, the peak excitation cross sections out of the two individual 4p(5)5s metastable levels are found to differ by 1 to 2 orders of magnitude. This is explained by the special features of the electronic structure of the two configurations involved. The peak cross sections are 10 to 1600 times larger than the corresponding peak cross sections out of the ground state.