Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Iodine molecule modifications with high pressure   Metallization and dissociation are key transformations in diatomic molecules
at high densities particularly significant for modeling giant planets. Using
X-ray absorption spectroscopy and atomistic modeling, we demonstrate that in
halogens, the formation of a \textit{connected} molecular structure takes place
at pressures well below metallization. Here we show that the iodine diatomic
molecule first elongates of $\sim$0.007 \AA~up to a critical pressure of $P_c$
$\backsim$7~GPa developing bonds between molecules. Then its length
continuously decreases with pressure up to 15-20~GPa. Universal trends in
halogens are shown and allow to predict for chlorine a pressure of 42$\pm$8~GPa
for molecular bond-length reversal. Our findings tackle the molecule
invariability paradigm in diatomic molecular phases at high pressures and may
be generalized to other abundant diatomic molecules in the universe, including
hydrogen.

9
The categories of this paper are: nlin
25
The categories of this paper are: patt-sol
14
The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
2
The categories of this paper are: math
15
The categories of this paper are: nucl-ex
8
The categories of this paper are: hep-ex
10
The categories of this paper are: q-bio
18
The categories of this paper are: econ
7
The categories of this paper are: hep-th
34
The categories of this paper are: chem-ph
36
The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
37
The categories of this paper are: supr-con
12
The categories of this paper are: nucl-th
17
The categories of this paper are: q-fin