Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Exchange-correlation Hole of the Si Atom, A Quantum Monte Carlo
  Study   We have studied the exchange-correlation hole and pair correlation function
in the valence shell of the ground-state of the Si atom, using accurate
Slater-Jastrow wavefunctions and the Variational Monte Carlo method. The
exchange-correlation hole shows a number of interesting features caused by the
open shell structure of Si, including a marked transition from efficient to
poor screening behavior as a test majority-spin electron is moved from the
center of a valence 3p orbital onto the axis perpendicular to the occupied 3p
orbitals. This behavior results from the dramatic difference in the exchange
hole in the two cases, which is partially compensated by a corresponding
anisotropy in the correlation hole. In addition we observe an anisotropic
change in the spin density induced by Coulomb correlation, reducing the spatial
overlap between the different spin-components of the density and contributing
to the anisotropy of the correlation hole. In contrast to the longer range
features, we find that the "on-top" correlation hole is well described by
linear density functional theory, for a large range of local density and
magnetization.

31
The categories of this paper are: ao-sci
8
The categories of this paper are: hep-ex
1
The categories of this paper are: cs
34
The categories of this paper are: chem-ph
7
The categories of this paper are: hep-th
30
The categories of this paper are: q-alg
21
The categories of this paper are: adap-org
15
The categories of this paper are: nucl-ex
28
The categories of this paper are: alg-geom
14
The categories of this paper are: math-ph
18
The categories of this paper are: econ
35
The categories of this paper are: mtrl-th
27
The categories of this paper are: comp-gas
24
The categories of this paper are: dg-ga
33
The categories of this paper are: plasm-ph
32
The categories of this paper are: atom-ph