{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,5]],"date-time":"2026-06-05T04:50:08Z","timestamp":1780635008753,"version":"3.54.1"},"reference-count":57,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2023,9,21]],"date-time":"2023-09-21T00:00:00Z","timestamp":1695254400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Chem."],"abstract":"<jats:p>The aminomethyl (\u2022CH<jats:sub>2<\/jats:sub>NH<jats:sub>2<\/jats:sub>) radical is generated from the photo-oxidation of methylamine in the troposphere and is an important precursor for new particle formation. The effect of ammonia and water on the gas-phase formation of methanimine (CH<jats:sub>2<\/jats:sub>NH) from the <jats:sup>\u2022<\/jats:sup>CH<jats:sub>2<\/jats:sub>NH<jats:sub>2<\/jats:sub> + O<jats:sub>2<\/jats:sub> reaction is not known. Therefore, in this study, the potential energy surfaces for <jats:sup>\u2022<\/jats:sup>CH<jats:sub>2<\/jats:sub>NH<jats:sub>2<\/jats:sub> + O<jats:sub>2<\/jats:sub> (+NH<jats:sub>3<\/jats:sub>\/H<jats:sub>2<\/jats:sub>O) were constructed using <jats:italic>ab initio<\/jats:italic>\/\/DFT, i.e., <jats:italic>coupled<\/jats:italic>-<jats:italic>cluster theory<\/jats:italic> (CCSD(T))\/\/hybrid-density functional theory, i.e., M06-2X with the 6-311++G (3df, 3pd) basis set. The Rice\u2212Ramsperger\u2212Kassel\u2212Marcus (RRKM)\/master equation (ME) simulation with Eckart\u2019s asymmetric tunneling was used to calculate the rate coefficients and branching fractions relevant to the troposphere. The results show 40% formation of CH<jats:sub>2<\/jats:sub>NH at the low-pressure (&amp;lt;1 bar) and 100% formation of CH<jats:sub>2<\/jats:sub>NH<jats:sub>2<\/jats:sub>OO<jats:sup>\u2022<\/jats:sup> at the high-pressure limit (HPL) condition. When an ammonia molecule is introduced into the reaction, there is a slight increase in the formation of CH<jats:sub>2<\/jats:sub>NH; however, when a water molecule is introduced into the reaction, the increase in the formation of CH<jats:sub>2<\/jats:sub>NH was from 40% to \u223c80%. The calculated rate coefficient for <jats:sup>\u2022<\/jats:sup>CH<jats:sub>2<\/jats:sub>NH<jats:sub>2<\/jats:sub> + O<jats:sub>2<\/jats:sub> (+NH<jats:sub>3<\/jats:sub>) [1.9 \u00d7 10<jats:sup>\u221223<\/jats:sup>\u00a0cm<jats:sup>3<\/jats:sup> molecule<jats:sup>\u22121<\/jats:sup> s<jats:sup>\u22121<\/jats:sup>] and for CH<jats:sub>2<\/jats:sub>NH<jats:sub>2<\/jats:sub> + O<jats:sub>2<\/jats:sub> (+H<jats:sub>2<\/jats:sub>O) [3.3 \u00d7 10<jats:sup>-17<\/jats:sup>\u00a0cm<jats:sup>3<\/jats:sup> molecule<jats:sup>-1<\/jats:sup> s<jats:sup>-1<\/jats:sup>] is at least twelve and six order magnitudes smaller than those for free <jats:sup>\u2022<\/jats:sup>CH<jats:sub>2<\/jats:sub>NH<jats:sub>2<\/jats:sub> + O<jats:sub>2<\/jats:sub> (2 \u00d7 10<jats:sup>\u221211<\/jats:sup>\u00a0cm<jats:sup>3<\/jats:sup> molecule<jats:sup>\u22121<\/jats:sup> s<jats:sup>\u22121<\/jats:sup> at 298\u00a0K) reactions, respectively. Our result is consistent with that of previous experimental and theoretical analysis and in good agreement with its isoelectronic analogous reaction. The work also provides a clear understanding of the formation of tropospheric carcinogenic compounds, i.e., hydrogen cyanide (HCN).<\/jats:p>","DOI":"10.3389\/fchem.2023.1243235","type":"journal-article","created":{"date-parts":[[2023,9,21]],"date-time":"2023-09-21T22:39:41Z","timestamp":1695335981000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":10,"title":["Can a single ammonia and water molecule enhance the formation of methanimine under tropospheric conditions?: kinetics of \u2022CH2NH2 + O2 (+NH3\/H2O)"],"prefix":"10.3389","volume":"11","author":[{"given":"Manas Ranjan","family":"Dash","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mohamad Akbar","family":"Ali","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2023,9,21]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"9965","DOI":"10.1039\/D2CP05874J","article-title":"Effect of formic acid on O2 + OHCHOH =HCOOH + HO2 reaction under tropospheric condition: Kinetics of cis and trans isomers","volume":"25","author":"Ali","year":"2023","journal-title":"Phys. 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