Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Anisotropic thermal expansion of bismuth from first principles   Some anisotropy in both mechanical and thermodynamical properties of bismuth
is expected. A combination of density functional theory total energy
calculations and density functional perturbation theory in the local density
approximation is used to compute the elastic constants at 0 K using a finite
strain approach and the thermal expansion tensor in the quasiharmonic
approximation. The overall agreement with experiment is good. Furthermore, the
anisotropy in the thermal expansion is found to arise from the anisotropy in
both the directional compressibilities and the directional Gr\"uneisen
functions.

23
The categories of this paper are: solv-int
14
The categories of this paper are: math-ph
12
The categories of this paper are: nucl-th
21
The categories of this paper are: adap-org
35
The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol
3
The categories of this paper are: physics
10
The categories of this paper are: q-bio
0
The categories of this paper are: hep-ph
9
The categories of this paper are: nlin
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
27
The categories of this paper are: comp-gas