Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Thermodynamic model for electron emission and negative- and positive-ion
  formation in keV molecular collisions   A statistical-type model is developed to describe the ion production and
electron emission in collisions of (molecular) ions with atoms. The model is
based on the Boltzmann population of the bound electronic energy levels of the
quasi molecule formed in the collision and the discretized continuum. The
discretization of the continuum is implemented by a free electron gas in a box
model assuming an effective square potential of the quasi molecule. The
temperature of the electron gas is calculated by taking into account a
thermodynamically adiabatic process due to the change of the effective volume
of the quasi molecule as the system evolves. The system may undergo a
transition with a small probability from the discretized continuum to the
states of the complementary continuum. It is assumed that these states are
decoupled from the thermodynamic time development. The decoupled states
overwhelmingly determine the yield of the asymptotically observed fragment
ions. The main motivation of this work is to describe the recently observed
$H^-$ ion production in $OH^+ + Ar$ collisions. The obtained differential cross
sections for $H^-$ formation, cation production and electron emission are close
to the experimental ones. Calculations for the atomic systems $O^+ + Ar$ and
$H^+ + Ar$ are also in reasonable agreement with the experiments indicating
that the model can be applied to a wide class of collisions.

22
The categories of this paper are: chao-dyn
15
The categories of this paper are: nucl-ex
16
The categories of this paper are: stat
9
The categories of this paper are: nlin
34
The categories of this paper are: chem-ph
20
The categories of this paper are: acc-phys
2
The categories of this paper are: math
1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
31
The categories of this paper are: ao-sci
35
The categories of this paper are: mtrl-th
27
The categories of this paper are: comp-gas
33
The categories of this paper are: plasm-ph
37
The categories of this paper are: supr-con
8
The categories of this paper are: hep-ex
25
The categories of this paper are: patt-sol