Ionization of Ammonia Nanoices with Adsorbed Methanol Molecules

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60461373%3A22340%2F18%3A43916698" target="_blank" >RIV/60461373:22340/18:43916698 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/61388955:_____/18:00495950

Výsledek na webu

<a href="https://pubs.acs.org/doi/10.1021/acs.jpca.8b07974" target="_blank" >https://pubs.acs.org/doi/10.1021/acs.jpca.8b07974</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1021/acs.jpca.8b07974" target="_blank" >10.1021/acs.jpca.8b07974</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Ionization of Ammonia Nanoices with Adsorbed Methanol Molecules

Popis výsledku v původním jazyce

Large ammonia clusters represent a model system of ices that are omnipresent throughout the space. The interaction of ammonia ices with other hydrogen-boding molecules such as methanol or water and their behavior upon an ionization are thus relevant in the astrochemical context. In this study, ammonia clusters (NH3)(N) with the mean size (N) over bar approximate to 230 were prepared in molecular beams and passed through a pickup cell in which methanol molecules were adsorbed. At the highest exploited pickup pressures, the average composition of (NH3)(N)(CH3OH)(M) clusters was estimated to be N:M approximate to 210:10. On the other hand, the electron ionization of these clusters yielded about 75% of methanol-containing fragments (NH3)(n)(CH3OH)(m)H+ compared to 25% contribution of pure ammonia (NH3)(n)H+ ions. On the basis of this substantial disproportion, we propose the following ionization mechanism: The prevailing ammonia is ionized in most cases, resulting in NH4+ core solvated most likely with four ammonia molecules, yielding the wellknown &quot;magic number&quot; structure (NH3)(4)NH4+. The methanol molecules exhibit a strong propensity for sticking to the fragment ion. We have also considered mechanisms of intracluster reactions. In most cases, proton transfer between ammonia units take place. The theoretical calculations suggested the proton transfer either from the methyl group or from the hydroxyl group of the ionized methanol molecule to ammonia to be the energetically open channels. However, the experiments with selectively deuterated methanols did not show any evidence for the D+ transfer from the CD3 group. The proton transfer from the hydroxyl group could not be excluded entirely or confirmed unambiguously by the experiment.

Název v anglickém jazyce

Ionization of Ammonia Nanoices with Adsorbed Methanol Molecules

Popis výsledku anglicky

Large ammonia clusters represent a model system of ices that are omnipresent throughout the space. The interaction of ammonia ices with other hydrogen-boding molecules such as methanol or water and their behavior upon an ionization are thus relevant in the astrochemical context. In this study, ammonia clusters (NH3)(N) with the mean size (N) over bar approximate to 230 were prepared in molecular beams and passed through a pickup cell in which methanol molecules were adsorbed. At the highest exploited pickup pressures, the average composition of (NH3)(N)(CH3OH)(M) clusters was estimated to be N:M approximate to 210:10. On the other hand, the electron ionization of these clusters yielded about 75% of methanol-containing fragments (NH3)(n)(CH3OH)(m)H+ compared to 25% contribution of pure ammonia (NH3)(n)H+ ions. On the basis of this substantial disproportion, we propose the following ionization mechanism: The prevailing ammonia is ionized in most cases, resulting in NH4+ core solvated most likely with four ammonia molecules, yielding the wellknown &quot;magic number&quot; structure (NH3)(4)NH4+. The methanol molecules exhibit a strong propensity for sticking to the fragment ion. We have also considered mechanisms of intracluster reactions. In most cases, proton transfer between ammonia units take place. The theoretical calculations suggested the proton transfer either from the methyl group or from the hydroxyl group of the ionized methanol molecule to ammonia to be the energetically open channels. However, the experiments with selectively deuterated methanols did not show any evidence for the D+ transfer from the CD3 group. The proton transfer from the hydroxyl group could not be excluded entirely or confirmed unambiguously by the experiment.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10403 - Physical chemistry

Projekt

<a href="/cs/project/GA17-04068S" target="_blank" >GA17-04068S: Molekulové klastry jako nano-reaktory pro chemii řízenou fotony a elektrony</a><br>

Návaznosti

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

Rok uplatnění

2018

Kód důvěrnosti údajů

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

Název periodika

Journal of Physical Chemistry A

ISSN

1089-5639

e-ISSN

—

Svazek periodika

122

Číslo periodika v rámci svazku

43

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

11

Strana od-do

8458-8468

Kód UT WoS článku

000449308300004

EID výsledku v databázi Scopus

2-s2.0-85055819539