Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Van der Waals Energies in Density Functional Theory   In principle, density functional theory yields the correct ground-state
densities and energies of electronic systems under the action of a static
external potential.
  However, traditional approximations fail to include Van der Waals energies
between separated systems. This paper proposes a practical procedure for
remedying this difficulty. Our method allows seamless calculations between
small and large inter-system distances. The asymptotic H-He and He--He
interactions are calculated as a first illustration, with very accurate
results.

18
The categories of this paper are: econ
25
The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
0
The categories of this paper are: hep-ph
10
The categories of this paper are: q-bio
32
The categories of this paper are: atom-ph
33
The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
12
The categories of this paper are: nucl-th
28
The categories of this paper are: alg-geom
24
The categories of this paper are: dg-ga
34
The categories of this paper are: chem-ph
6
The categories of this paper are: astro-ph
16
The categories of this paper are: stat
20
The categories of this paper are: acc-phys
22
The categories of this paper are: chao-dyn