Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ab initio study of helium and hydrogen interactions in $\alpha$-Fe   Density Functional Theory (DFT) calculations show a weak interaction between
hydrogen and helium in iron, in contrast to previous reports of a strong
trapping of hydrogen at helium. The strong preference of He and H to occupy
regions with low electronic density (such as vacancies) explains this
discrepancy, with vacancy-He and vacancy-H binding forces concealing the
repulsive interaction between He and H. Furthermore, Rate Theory simulations
based on our DFT-calculated V$_n$He$_m$H$_p$ cluster energetics predict, as it
is observed in some experiments, that synergetic effects could be expected
between H and He in iron under irradiation.

22
The categories of this paper are: chao-dyn
35
The categories of this paper are: mtrl-th
25
The categories of this paper are: patt-sol
23
The categories of this paper are: solv-int
24
The categories of this paper are: dg-ga
36
The categories of this paper are: cmp-lg
34
The categories of this paper are: chem-ph
14
The categories of this paper are: math-ph
2
The categories of this paper are: math
37
The categories of this paper are: supr-con
7
The categories of this paper are: hep-th
5
The categories of this paper are: gr-qc
8
The categories of this paper are: hep-ex
1
The categories of this paper are: cs
15
The categories of this paper are: nucl-ex
31
The categories of this paper are: ao-sci