Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Phase space structures causing the reaction rate decrease in the
  collinear hydrogen exchange reaction   The collinear hydrogen exchange reaction is a paradigm system for
understanding chemical reactions. It is the simplest imaginable atomic system
with $2$ degrees of freedom modeling a chemical reaction, yet it exhibits
behaviour that is still not well understood - the reaction rate decreases as a
function of energy beyond a critical value. Using lobe dynamics we show how
invariant manifolds of unstable periodic orbits guide trajectories in phase
space. From the structure of the invariant manifolds we deduce that
insufficient transfer of energy between the degrees of freedom causes a
reaction rate decrease. In physical terms this corresponds to the free hydrogen
atom repelling the whole molecule instead of only one atom from the molecule.
We further derive upper and lower bounds of the reaction rate, which are
desirable for practical reasons.

6
The categories of this paper are: astro-ph
1
The categories of this paper are: cs
36
The categories of this paper are: cmp-lg
17
The categories of this paper are: q-fin
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
18
The categories of this paper are: econ
30
The categories of this paper are: q-alg
20
The categories of this paper are: acc-phys
16
The categories of this paper are: stat
0
The categories of this paper are: hep-ph
31
The categories of this paper are: ao-sci
37
The categories of this paper are: supr-con
5
The categories of this paper are: gr-qc
35
The categories of this paper are: mtrl-th
22
The categories of this paper are: chao-dyn