Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hydrogen-doped cubic diamond and the crystal structure of n-diamond   To understand the crystal structure of n-diamond, a hydrogen-doped (H-doped)
diamond model has been investigated using first principles calculations. In
particular, hydrogen concentration dependent elastic constants and lattice
parameters for the H-doped diamond have been analyzed. Our results indicate
that when the hydrogen concentration is less than 19 at.%, the H-doped diamond
is mechanically stable. When the hydrogen concentration is about 4 at.%, the
optimized lattice parameter, simulated XRD pattern and electronic properties
for the H-doped diamond all agree well with the corresponding experimental
values of n-diamond. The results imply that the n-diamond is likely to be an
H-doped diamond.

9
The categories of this paper are: nlin
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
0
The categories of this paper are: hep-ph
6
The categories of this paper are: astro-ph
16
The categories of this paper are: stat
36
The categories of this paper are: cmp-lg
14
The categories of this paper are: math-ph
31
The categories of this paper are: ao-sci
30
The categories of this paper are: q-alg
33
The categories of this paper are: plasm-ph
12
The categories of this paper are: nucl-th
18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph
2
The categories of this paper are: math