Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Diffusion of Small Molecules in Metal Organic Framework Materials   Ab initio simulations are combined with in situ infrared spectroscopy to
unveil the molecular transport of H$_2$, CO$_2$, and H$_2$O in the metal
organic framework MOF-74-Mg. Our study uncovers---at the atomistic level---the
major factors governing the transport mechanism of these small molecules. In
particular, we identify four key diffusion mechanisms and calculate the
corresponding diffusion barriers, which are nicely confirmed by time-resolved
infrared experiments. We also answer a long-standing question about the
existence of secondary adsorption sites for the guest molecules, and we show
how those sites affect the macroscopic diffusion properties. Our findings are
important to gain a fundamental understanding of the diffusion processes in
these nano-porous materials, with direct implications for the usability of MOFs
in gas sequestration and storage applications.

36
The categories of this paper are: cmp-lg
31
The categories of this paper are: ao-sci
18
The categories of this paper are: econ
1
The categories of this paper are: cs
17
The categories of this paper are: q-fin
8
The categories of this paper are: hep-ex
2
The categories of this paper are: math
10
The categories of this paper are: q-bio
20
The categories of this paper are: acc-phys
37
The categories of this paper are: supr-con
32
The categories of this paper are: atom-ph
19
The categories of this paper are: eess
28
The categories of this paper are: alg-geom
7
The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph