Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Molecular dynamics simulation study of self-diffusion for
  penetrable-sphere model fluids   Molecular dynamics simulations are carried out to investigate the diffusion
behavior of penetrable-sphere model fluids characterized by a finite energy
barrier $\epsilon$. The self-diffusion coefficient is evaluated from the
time-dependent velocity autocorrelation function and mean-square displacement.
Detailed insights into the cluster formation for penetrable spheres are gained
from the Enskog factor, the effective particle volume fraction, the mean free
path, and the collision frequency for both the soft-type penetrable and the
hard-type reflective collisions. The simulation data are compared to
theoretical predictions from the Boltzmann kinetic equation and from a simple
extension to finite $\epsilon$ of the Enskog prediction for impenetrable hard
spheres ($\epsilon\to\infty$). A reasonable agreement between theoretical and
simulation results is found in the cases of $\epsilon^*\equiv
\epsilon/k_BT=0.2$, $0.5$, and $1.0$. However, for dense systems (packing
fraction $\phi>0.6$) with a highly repulsive energy barrier ($\epsilon^*=3.0$),
a poorer agreement was observed due to metastable static effects of clustering
formation and dynamic effects of correlated collision processes among these
cluster-forming particles.

18
The categories of this paper are: econ
10
The categories of this paper are: q-bio
9
The categories of this paper are: nlin
16
The categories of this paper are: stat
3
The categories of this paper are: physics
15
The categories of this paper are: nucl-ex
17
The categories of this paper are: q-fin
19
The categories of this paper are: eess
22
The categories of this paper are: chao-dyn
29
The categories of this paper are: funct-an
27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph
26
The categories of this paper are: bayes-an
11
The categories of this paper are: hep-lat
23
The categories of this paper are: solv-int
30
The categories of this paper are: q-alg