Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Experimental and theoretical study of oxygen adsorption structures on
  Ag(111)   The oxidized Ag(111) surface has been studied by a combination of
experimental and theoretical methods, scanning tunneling microscopy (STM),
x-ray photoelectron spectroscopy (XPS), and density functional theory (DFT). A
large variety of different surface structures is found, depending on the
detailed preparation conditions. The observed structures fall into four
classes: (a) individually chemisorbed atomic oxygen atoms, (b) three different
oxygen overlayer structures, including the well-known p(4 x 4) phase, formed
from the same Ag$_6$ and Ag$_{10}$ building blocks, (c) a c(4 x 8) structure
not previously observed, and (d) at higher oxygen coverages structures
characterized by stripes along the high-symmetry directions of the Ag(111)
substrate. Our analysis provides a detailed explanation of the atomic-scale
geometry of the Ag$_6$/Ag$_{10}$ building block structures, and the c(4 x 8)
and stripe structures are discussed in detail. The observation of many
different and co-existing structures implies that the O/Ag(111) system is
characterized by a significantly larger degree of complexity than previously
anticipated, and this will impact our understanding of oxidation catalysis
processes on Ag catalysts.

15
The categories of this paper are: nucl-ex
10
The categories of this paper are: q-bio
0
The categories of this paper are: hep-ph
22
The categories of this paper are: chao-dyn
37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga
28
The categories of this paper are: alg-geom
23
The categories of this paper are: solv-int
17
The categories of this paper are: q-fin
12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
19
The categories of this paper are: eess
34
The categories of this paper are: chem-ph
1
The categories of this paper are: cs
5
The categories of this paper are: gr-qc
18
The categories of this paper are: econ