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

Kód výsledku v 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>

Výsledek na webu

<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>

Jazyk výsledku

angličtina

Název v původním jazyce

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

Popis výsledku v původním jazyce

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 -&gt; NH3+ + H and NH3+ + H-2 -&gt; 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 (&gt;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.

Název v anglickém jazyce

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

Popis výsledku anglicky

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 -&gt; NH3+ + H and NH3+ + H-2 -&gt; 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 (&gt;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.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10305 - Fluids and plasma physics (including surface physics)

Projekt

<a href="/cs/project/GA23-05439S" target="_blank" >GA23-05439S: Rekombinace astrofyzikálně významných iontů ve specifickém kvantovém stavu s elektrony</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2025

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Astronomy &amp; Astrophysics

ISSN

0004-6361

e-ISSN

1432-0746

Svazek periodika

704

Číslo periodika v rámci svazku

Dec

Stát vydavatele periodika

FR - Francouzská republika

Počet stran výsledku

5

Strana od-do

A111

Kód UT WoS článku

001633255500011

EID výsledku v databázi Scopus

2-s2.0-105024707618