Increase of the Charge Transfer Rate Coefficients for NO+ and O2+• Reactions with Isoprene Molecules at Elevated Interaction Energies
Result description
Atmospheric concentrations of isoprene (2-methylbutadiene) in environmental research and in exhaled breath for medical research are usually measured by soft chemical ionization mass spectrometry that relies on a knowledge of the kinetics of the gas phase reactions of H3O+, NO+ or O2+• ions with isoprene molecules. Thus, we have carried out an experimental study of the rate coefficients, k, and product ions distributions for such reactions over a range of ion–molecule interaction energy, Er, (0.05–0.8 eV) in a helium-buffered selected ion flow-drift tube, SIFDT. It is found that contrary to the ion-induced dipole capture model, k for the NO+ and O2+• charge transfer reactions almost doubled over the Er range, while k for the H3O+ proton transfer reaction did not significantly change with Er, as predicted. These results reveal that the reaction mechanism involving ion–molecule capture forming an intermediate complex does not properly describe charge transfer to isoprene molecules. It is important to account for this increase in k with Er in these isoprene charge transfer reactions, and probably for other such reactions, when using drift tube reactors for trace gas analysis.
Keywords
The result's identifiers
Result code in IS VaVaI
Result on the web
DOI - Digital Object Identifier
Alternative languages
Result language
angličtina
Original language name
Increase of the Charge Transfer Rate Coefficients for NO+ and O2+• Reactions with Isoprene Molecules at Elevated Interaction Energies
Original language description
Atmospheric concentrations of isoprene (2-methylbutadiene) in environmental research and in exhaled breath for medical research are usually measured by soft chemical ionization mass spectrometry that relies on a knowledge of the kinetics of the gas phase reactions of H3O+, NO+ or O2+• ions with isoprene molecules. Thus, we have carried out an experimental study of the rate coefficients, k, and product ions distributions for such reactions over a range of ion–molecule interaction energy, Er, (0.05–0.8 eV) in a helium-buffered selected ion flow-drift tube, SIFDT. It is found that contrary to the ion-induced dipole capture model, k for the NO+ and O2+• charge transfer reactions almost doubled over the Er range, while k for the H3O+ proton transfer reaction did not significantly change with Er, as predicted. These results reveal that the reaction mechanism involving ion–molecule capture forming an intermediate complex does not properly describe charge transfer to isoprene molecules. It is important to account for this increase in k with Er in these isoprene charge transfer reactions, and probably for other such reactions, when using drift tube reactors for trace gas analysis.
Czech name
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Czech description
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Classification
Type
Jimp - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10403 - Physical chemistry
Result continuities
Project
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)
Others
Publication year
2018
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Journal of Physical Chemistry A
ISSN
1089-5639
e-ISSN
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Volume of the periodical
122
Issue of the periodical within the volume
51
Country of publishing house
US - UNITED STATES
Number of pages
5
Pages from-to
9733-9737
UT code for WoS article
000454751300001
EID of the result in the Scopus database
2-s2.0-85059801346
Basic information
Result type
Jimp - Article in a specialist periodical, which is included in the Web of Science database
OECD FORD
Physical chemistry
Year of implementation
2018