Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantitative study of molecular N_2 trapped in disordered GaN:O films   The structure of disordered GaN:O films grown by ion-assisted deposition is
investigated using x-ray absorption near-edge spectroscopy and Raman
spectroscopy. It is found that between 4 and 21 % of the nitrogen in the films
is in the form of molecular N_2 that interacts only weakly with the surrounding
matrix. The anion to cation ratio in the GaN:O host remains close to unity, and
there is a close correlation between the N_2 fraction, the level of oxygen
impurities, and the absence of short-range order in the GaN:O matrix.

21
The categories of this paper are: adap-org
3
The categories of this paper are: physics
9
The categories of this paper are: nlin
22
The categories of this paper are: chao-dyn
15
The categories of this paper are: nucl-ex
20
The categories of this paper are: acc-phys
8
The categories of this paper are: hep-ex
18
The categories of this paper are: econ
35
The categories of this paper are: mtrl-th
1
The categories of this paper are: cs
11
The categories of this paper are: hep-lat
16
The categories of this paper are: stat
29
The categories of this paper are: funct-an
23
The categories of this paper are: solv-int
27
The categories of this paper are: comp-gas
13
The categories of this paper are: quant-ph