Decay of hollow atoms above and below a surface

Multiple ionization of iodine for 2.5-5.0 MeV I22+ ions impacting on Fe target

The L-shell X-ray emissions of iodine are investigated as a function of the incident energy for I²²⁺ ions impacting on Fe target in the energy region near the Bohr velocity. Six distinct L-subshell X-rays, Lι, Lα_{1, 2}, Lβ_{1, 3, 4}, Lβ_{2, 15}, Lγ₁ and Lγ_{2, 3, 4, 4}^', are observed. Compared to the atomic data, the energy of the experimental X ray shifts to the higher energy side. The relative intensity ratios of Lι, Lβ_{1, 3, 4}, Lβ_{2, 15}, to Lα_{1, 2}, Lι to Lβ_{2, 15} and Lγ_{2, 3, 4, 4/} to Lγ₁ are enhanced, but has no obvious change with the increase of projectile energy in the present energy region. That is interpreted by the multiple ionization effect of the M-, N- and O-shell electrons.

Photon Emission from Hollow Ions Near Surfaces

Ions with multiple inner-shell vacancies frequently arise due to their interaction with different targets, such as (intense) light pulses, atoms, clusters or bulk material. They are formed, in addition, if highly charged ions approach surfaces and capture electrons at rather large distances. To explore the interaction of such hollow ions and their subsequent relaxation, photon spectra in different frequency regions have been measured and compared to calculations. To support these and related measurements, we here show within the framework of the Jena Atomic Calculator (Jac) how (additional) electrons in outer shells modify photon emission and lead to characteristic shifts in the observed spectra. Further, for highly charged Ar ions in KLm(m=1…8) configurations, we analyze the mean relaxation time for their stabilization into the different ground configurations. These examples demonstrate how a powerful and flexible toolbox such as Jac will be useful (and necessary) in order to model the photon and electron emission of ions as they occur not only near surfaces but also in astro-, atomic and plasma physics.

Multiple ionization state of Arq+ ions during collisions near the Bohr velocity

In order to clarify the mechanism and the influence of the initial charge state and target atomic parameters for the formation of L-shell multiple ionization state of Ar^q+ ions produced by the collisions near the Bohr velocity, the k-shell x-ray emission of Ar is measured for 1.2 MeV Ar^{q+(q=4, 6, 8, 9, 11, 12)} ions impacting on V target and 3 MeV Ar¹¹⁺ ions interacting with selected targets (Z₂ = 23, 26, 27, 28, 29, 30). It is found that the measured Ar Kα and Kβ x-ray energies shift to the high energy side, and the relative intensity ratios of Kβ/Kα are enlarged than the atomic data, owing to the presence of out-shell multiple vacancies. The multiple ionization is almost independence of the projectile charge state, but is diminished with increasing target atomic number.