EXCITONIC SIDE BANDS OF INNER-SHELL EXCITATIONS IN RARE GAS SOLIDS

Valence-exciton luminescence under inner-shell excitation of the rare gas solids Xe, Kr, and Ar has been measured using time-resolved photoluminescence. Two different processes for exciton creation can be distinguished: creation of "prompt" excitons immediately after excitation (within the experimental time resolution), and creation of "delayed" excitons through electron–hole recombination. The decay structure of the exciton emission in the range of inner-shell excitation is characterized by the coexistence of the two processes. Time-resolved excitation spectra near the 2p edge in Ar, the 3d edge in Kr, and the 4d edge in Xe are discussed. The process of prompt exciton creation is strongly enhanced above an excitation threshold at the energy position of the ionization limit of the core state plus the energy of the valence free exciton.

Observation and analysis (synthesis) of X-ray spectrum originated from electron capture of low-energy, highly charged Xeq+ (q = 26–43) ions in single collisions with Ar atom

X-rays have been observed in collisions of low-energy (keV/u), highly charged Xeq+ (q = 26–43) ions with neutral Ar atoms. These X-rays are understood to be produced through electron capture by highly charged projectile ions from target atoms, the electrons then cascade down to the ground state. It is clearly noted that the most intense X-ray peaks correspond to M-shell – N-shell transitions with different numbers of M-shell vacancies and that X-ray intensities decrease significantly toward high energies near the ionization limit. This observation indicates that the direct transition of an electron captured in a highly excited state to M-shell vacancies is negligibly small. To obtain a better understanding of X-ray production mechanisms, we tried to synthesize the expected X-ray spectrum and compare that with the observed spectrum. The synthesized spectra were found to reproduce the observed spectra reasonably well. PACS Nos: 32.30Rj, 32.70Cs, 32.80Rm, 34.70+e