Reinterpreting the infrared spectrum of H plus HCN: Methylene amidogen radical and its coproducts

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dc.contributor.author Wiens, Avery E.
dc.contributor.author Copan, Andreas V.
dc.contributor.author Rossomme, Elliot C.
dc.contributor.author Aroeira, Gustavo J. R. [UNIFESP]
dc.contributor.author Bernstein, Olivia M.
dc.contributor.author Agarwal, Jay
dc.contributor.author Schaefer, Henry F.
dc.date.accessioned 2020-07-08T13:09:53Z
dc.date.available 2020-07-08T13:09:53Z
dc.date.issued 2018
dc.identifier http://dx.doi.org/10.1063/1.5004984
dc.identifier.citation Journal Of Chemical Physics. Melville, v. 148, n. 1, p. -, 2018.
dc.identifier.issn 0021-9606
dc.identifier.uri https://repositorio.unifesp.br/handle/11600/54272
dc.description.abstract The methylene amidogen radical (H2CN) plays a role in high-energy material combustion and extrater-resterial atmospheres. Recent theoretical work has struggled to match experimental assignments for its CN and antisymmetric CH2 stretching frequencies (nu(2) and nu(5)), which were reported to occur at 1725 and 3103 cm(-1). Herein, we compute the vibrational energy levels of this molecule by extrapolating quadruples-level coupled-cluster theory to the complete basis limit and adding corrections for vibrational anharmonicity. This level of theory predicts that nu(2) and nu(5) should occur at 1646 and 2892 cm(-1), at odds with the experimental assignments. To investigate the possibility of defects in our theoretical treatment, we analyze the sensitivity of our approach to each of its contributing approximations. Our analysis suggests that the observed deviation from experiment is too large to be explained as an accumulation of errors, leading us to conclude that these transitions were misassigned. To help resolve this discrepancy, we investigate possible byproducts of the H + HCN reaction, which was the source of H2CN in the original experiment. In particular, we predict vibrational spectra for cis-HCNH, trans-HCNH, and H2CNH using high-level coupled-cluster computations. Based on these results, we reassign the transition at 1725 cm(-1) to nu(3) of trans-HCNH, yielding excellent agreement. Supporting this identification, we assign a known contaminant peak at 886 cm(-1) to nu(5) of the same conformer. Our computations suggest that the peak observed at 3103 cm(-1), however, does not belong to any of the aforementioned species. To facilitate further investigation, we use structure and bonding arguments to narrow the range of possible candidates. These arguments lead us to tentatively put forth formaldazine [(H2CN)(2)] as a suggestion for further study, which we support with additional computations. Published by AIP Publishing. en
dc.description.sponsorship Department of Energy, Office of Basic Energy Sciences, Computational and Theoretical Chemistry (CTC) Program
dc.format.extent -
dc.language.iso eng
dc.publisher Amer Inst Physics
dc.relation.ispartof Journal Of Chemical Physics
dc.rights Acesso restrito
dc.title Reinterpreting the infrared spectrum of H plus HCN: Methylene amidogen radical and its coproducts en
dc.type Artigo
dc.description.affiliation Univ Georgia, Ctr Computat Quantum Chem, Athens, GA 30602 USA
dc.description.affiliation Messiah Coll, Dept Chem & Biochem, Mechanicsburg, PA 17055 USA
dc.description.affiliation Univ Fed Sao Paulo, Inst Environm Chem & Pharmaceut Sci, Sao Paulo, Brazil
dc.description.affiliation Biola Univ, Dept Chem Phys & Engn, La Mirada, CA 90639 USA
dc.description.affiliationUnifesp Univ Fed Sao Paulo, Inst Environm Chem & Pharmaceut Sci, Sao Paulo, Brazil
dc.description.sponsorshipID Department of Energy, Office of Basic Energy Sciences, Computational and Theoretical Chemistry (CTC) Program: DE-SC0018412
dc.identifier.doi 10.1063/1.5004984
dc.description.source Web of Science
dc.identifier.wos WOS:000419394500017
dc.coverage Melville
dc.citation.volume 148
dc.citation.issue 1



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