Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The effect of ionization on the global minima of small and medium sized
  silicon and magnesium clusters   We re-examine the question of whether the geometrical ground state of neutral
and ionized clusters are identical. Using a well defined criterion for being
"identical" together, the extensive sampling methods on a potential energy
surface calculated by density functional theory, we show that the ground states
are in general different. This behavior is to be expected whenever there are
metastable configurations which are close in energy to the ground state, but it
disagrees with previous studies.

19
The categories of this paper are: eess
18
The categories of this paper are: econ
6
The categories of this paper are: astro-ph
5
The categories of this paper are: gr-qc
7
The categories of this paper are: hep-th
35
The categories of this paper are: mtrl-th
32
The categories of this paper are: atom-ph
1
The categories of this paper are: cs
33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci
20
The categories of this paper are: acc-phys
36
The categories of this paper are: cmp-lg
4
The categories of this paper are: cond-mat
10
The categories of this paper are: q-bio
9
The categories of this paper are: nlin
22
The categories of this paper are: chao-dyn