Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Molecular dynamics simulation of nanocolloidal amorphous silica
  particles: Part II   Explicit molecular dynamics simulations were applied to a pair of amorphous
silica nanoparticles of diameter 3.2 nm immersed in a background electrolyte.
Mean forces acting between the pair of silica nanoparticles were extracted at
four different background electrolyte concentrations. Dependence of the
inter-particle potential of mean force on the separation and the silicon to
sodium ratio, as well as on the background electrolyte concentration, are
demonstrated. The pH was indirectly accounted for via the ratio of silicon to
sodium used in the simulations. The nature of the interaction of the
counter-ions with charged silica surface sites (deprotonated silanols) was also
investigated. The effect of the sodium double layer on the water ordering was
investigated for three Si:Na+ ratios. The number of water molecules trapped
inside the nanoparticles was investigated as the Si:Na+ ratio was varied.
Differences in this number between the two nanoparticles in the simulations are
attributed to differences in the calculated electric dipole moment. The
implications of the form of the potentials for aggregation are also discussed.

31
The categories of this paper are: ao-sci
13
The categories of this paper are: quant-ph
7
The categories of this paper are: hep-th
16
The categories of this paper are: stat
4
The categories of this paper are: cond-mat
30
The categories of this paper are: q-alg
19
The categories of this paper are: eess
28
The categories of this paper are: alg-geom
1
The categories of this paper are: cs
8
The categories of this paper are: hep-ex
20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph