The Journal of Physical Chemistry A
ARTICLE
High LET. In general, the H2O2 yield is expected to increase
initially with increasing LET due to the increased probability of
intratrack reactions between OH radicals. At very high LET,
higher order intratrack reactions of radicals with H2O2 lead to a
subsequent decrease in H2O2 yields. All the systems studied in
the present work follow this general trend. In addition to these
intratrack reactions, the chemistry of the H2O2 in the homo-
geneous phase can be important at low LET where the radical
escape yield is reasonably high.
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The pH dependence of the measured H2O2 yields is strongly
governed by the influence of e- and H atom chemistry in the
aq
homogeneous phase of radiolysis, which in turn is determined by the
radical escape yield and the scavenging capacity. In the acrylamide
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of homogeneous chemistry at LET lower than 20.7 (5 MeV H ions)
and 156 eV/nm (5 MeV He ions), respectively.
At LET above 100 eV/nm all the studied systems show constant
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’ ACKNOWLEDGMENT
The authors thank Prof. Michael Wiescher for making the
facilities of the Notre Dame Nuclear Science Laboratory available
to us. The Nuclear Science Laboratory is supported by the U.S.
National Science Foundation. The Notre Dame Radiation
Laboratory is supported by the Office of Basic Energy Sciences
of the U.S. Department of Energy. This contribution is NDRL-
4869 from the Notre Dame Radiation Laboratory.
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dx.doi.org/10.1021/jp1099927 |J. Phys. Chem. A 2011, 115, 700–708