Nuclear spin effects in ammonia chemistry: Ion trap study of NH3+ and NH4+ formation

Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F25%3A10510124" target="_blank" >RIV/00216208:11320/25:10510124 - isvavai.cz</a>
Result on the web
<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=6gWbz2_jN_" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=6gWbz2_jN_</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1051/0004-6361/202557636" target="_blank" >10.1051/0004-6361/202557636</a>

Result language
angličtina
Original language name
Nuclear spin effects in ammonia chemistry: Ion trap study of NH3+ and NH4+ formation
Original language description
Aims. We investigate whether the nuclear-spin state of H-2 (ortho or para state) modifies the kinetics of two key reactions in ammonia formation in the interstellar medium: NH2+ + H-2 -> NH3+ + H and NH3+ + H-2 -> NH4+ + H. Methods. The reaction rate coefficients were measured in a cryogenic 22-pole radiofrequency ion trap over 15-270 K using normal H-2 (ortho-to-para ratio 3 : 1) and para-enriched H-2 (99.5% para-H-2) produced by catalytic conversion at approximate to 15 K. Results. For NH2+ + H-2, the reaction rate coefficients are in the range 10(-10)-10(-9) cm(3) s(-1) with a weak negative temperature dependence. For NH3+ + H-2, the reaction rate coefficients exhibit an Arrhenius dependence with an activation energy of approximate to 90 meV at high temperatures (>100 K), combined with an increasing value towards low temperatures (10-100 K) due to quantum tunneling. In the studied range of temperatures, the reaction rate coefficients obtained with para-enriched and normal H-2 are indistinguishable within the experimental uncertainty for both reactions.
Czech name
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Czech description
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Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
—
OECD FORD branch
10305 - Fluids and plasma physics (including surface physics)

Project
<a href="/en/project/GA23-05439S" target="_blank" >GA23-05439S: State specific recombination of astrophysically important ions with electrons</a><br>
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year
2025
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

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