Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Molecular structure and reversible photodegradation in anthraquinone
  dyes   Reversible photodegradation is a process that has been observed in several
dye molecules, but the underlying mechanisms are not still well understood. In
this contribution, we characterize a series of anthraquinone dyes to determine
how self-healing depends on molecular structure. Past studies have used probing
techniques that rely on linear absorption, two-photon fluorescence, and
amplified spontaneous emission. Each of these probes provide an indirect
measure of the populations of the damaged and undamaged species, requiring
calibrations or assumptions to be made that might affect the accuracy of the
results. The present studies use fluorescence as a probe, which is shown to
directly measure the undamaged population. It is found that certain
anthraquinone classes share common structural features that are associated with
self healing. Furthermore, the time and temperature dependence of
photodegradation and self-healing is found to be consistent with the domain
model of self healing.

12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex
25
The categories of this paper are: patt-sol
2
The categories of this paper are: math
28
The categories of this paper are: alg-geom
32
The categories of this paper are: atom-ph
1
The categories of this paper are: cs
14
The categories of this paper are: math-ph
37
The categories of this paper are: supr-con
19
The categories of this paper are: eess
30
The categories of this paper are: q-alg
16
The categories of this paper are: stat
20
The categories of this paper are: acc-phys
7
The categories of this paper are: hep-th
6
The categories of this paper are: astro-ph
0
The categories of this paper are: hep-ph