Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Unusual charge exchange by swift heavy ions at solid surfaces   We have employed x-ray spectroscopy to probe the charge changing process only
in the bulk of the foil when swift heavy ions pass through it. In contrast, the
electromagnetic methods take into account integral effect of the charge
changing process in the bulk as well as the charge exchange phenomenon at the
surface of the foil. Thus, the difference between the mean charge states so
measured from the two methods disentangles the charge exchange phenomenon at
the surface from the charge changing process in the bulk and, provides
opportunities to refine the understanding of ion-surface interactions. Very
surprisingly, up to tens of electrons per event participate in the charge
exchange phenomenon during swift heavy ion-surface interactions. This finding
has been validated with a series of experiments using several ions (z = 22-35)
in the energy range of 1.5-3.0 MeV/u and also verified theoretically with
Fermi-gas model. Interestingly, such unusual charge exchange phenomenon could
play significant role in x-ray emission of many astrophysical environments,
infrared emission bands from range of environments in galaxies, accelerator
physics, ion energy losses in solids, heavy ion cancer treatments, inner shell
ionization by heavy ions, and surface modifications in nano scale.

5
The categories of this paper are: gr-qc
18
The categories of this paper are: econ
17
The categories of this paper are: q-fin
15
The categories of this paper are: nucl-ex
30
The categories of this paper are: q-alg
9
The categories of this paper are: nlin
26
The categories of this paper are: bayes-an
1
The categories of this paper are: cs
31
The categories of this paper are: ao-sci
6
The categories of this paper are: astro-ph
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con
13
The categories of this paper are: quant-ph
8
The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
35
The categories of this paper are: mtrl-th