Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Mesophase Formation Stabilizes High-Purity Magic-Sized Clusters   Magic-sized clusters (MSCs) are renowned for their identical size and
closed-shell stability that inhibit conventional nanoparticle (NP) growth
processes. Though MSCs have been of increasing interest, understanding the
reaction pathways toward their nucleation and stabilization is an outstanding
issue. In this work, we demonstrate that high concentration synthesis (1000 mM)
promotes a well-defined reaction pathway to form high-purity MSCs (greater than
99.9 percent). The MSCs are resistant to typical growth and dissolution
processes. Based on insights from in-situ X-ray scattering analysis, we
attribute this stability to the accompanying production of a large, hexagonal
organic-inorganic mesophase (greater than 100 nm grain size) that arrests
growth of the MSCs and prevents NP growth. At intermediate concentrations (500
mM), the MSC mesophase forms, but is unstable, resulting in NP growth at the
expense of the assemblies. These results provide an alternate explanation for
the high stability of MSCs. Whereas the conventional mantra has been that the
stability of MSCs derives from the precise arrangement of the inorganic
structures (i.e., closed-shell atomic packing), we demonstrate that anisotropic
clusters can also be stabilized by self-forming fibrous mesophase assemblies.
At lower concentration (less than 200 mM or greater than 16 acid-to-metal),
MSCs are further destabilized and NPs formation dominates that of MSCs.
Overall, the high concentration approach intensifies and showcases inherent
concentration-dependent surfactant phase behavior that is not accessible in
conventional (i.e., dilute) conditions. This work provides not only a robust
method to synthesize, stabilize, and study identical MSC products, but also
uncovers an underappreciated stabilizing interaction between surfactants and
clusters.

30
The categories of this paper are: q-alg
27
The categories of this paper are: comp-gas
37
The categories of this paper are: supr-con
15
The categories of this paper are: nucl-ex
7
The categories of this paper are: hep-th
34
The categories of this paper are: chem-ph
32
The categories of this paper are: atom-ph
28
The categories of this paper are: alg-geom
0
The categories of this paper are: hep-ph
26
The categories of this paper are: bayes-an
35
The categories of this paper are: mtrl-th
16
The categories of this paper are: stat
33
The categories of this paper are: plasm-ph
21
The categories of this paper are: adap-org
19
The categories of this paper are: eess
20
The categories of this paper are: acc-phys