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Semiempirical scaling laws for electron capture at low energies

1996; American Physical Society; Volume: 54; Issue: 5 Linguagem: Inglês

10.1103/physreva.54.4127

1538-4446

N. Selberg, C. Biedermann, H. Cederquist,

Atomic and Molecular Physics

We present semiempirical scaling laws for different electronic rearrangement features in slow collisions with ions of high charge q. The absolute cross section for removing exactly r electrons from the target is found to be well described by the scaling (sc) relation $^{\mathit{sc}}\mathrm{\ensuremath{\sigma}}_{\mathit{q}}^{\mathit{r}}$=(2.7\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}13}$)qr/[${\mathit{I}}_{1}^{2}$${\mathit{I}}^{2}$ dr${\ensuremath{\sum}}_{\mathit{j}=1}^{\mathit{j}=\mathit{N}}$(j/${\mathit{I}}_{\mathit{j}}^{2}$)] ${\mathrm{cm}}^{2}$, where ${\mathit{I}}_{\mathit{j}}$ is the jth target ionization potential in eV, and N is the number of outer-shell electrons. This expression and the related total recoil-ion charge-state fractions, $^{\mathit{sc}}$${\mathit{f}}_{\mathit{q}}^{\mathit{r}}$${=}^{\mathit{sc}}$${\mathrm{\ensuremath{\sigma}}}_{\mathit{q}}^{\mathit{r}}$/${\ensuremath{\sum}}_{\mathit{r}}^{\mathit{sc}}$\ensuremath{\sigma} $_{\mathit{q}}^{\mathit{r}}$, compare favorably with recent experimental results ${(}^{\mathit{ex}}$${\mathrm{\ensuremath{\sigma}}}_{\mathit{q},\mathit{q}\mathrm{\ensuremath{-}}\mathit{p}}^{\mathit{r}}$) for slow ${\mathrm{Xe}}^{\mathit{q}+}$ ions (15\ensuremath{\leqslant}q\ensuremath{\leqslant}43) colliding with He, Ar, and Xe. We discuss the possibility of establishing scaling laws for phenomenological cross sections ${\mathrm{\ensuremath{\sigma}}}_{\mathit{q},\mathit{q}\mathrm{\ensuremath{-}}\mathit{p}}$, where only the number of electrons retained by the projectile p is specified. \textcopyright{} 1996 The American Physical Society.