Theoretical Rotational and Vibrational Spectral Data for the Hypermagnesium Oxide Species Mg2O and Mg2O.
Chemphyschem
; 25(17): e202400479, 2024 Sep 02.
Article
en En
| MEDLINE
| ID: mdl-38801234
ABSTRACT
While magnesium is astronomically observed in small molecules, it largely serves as a contributor to silicate grains, though how these grains form is not well-understood. The smallest hypermagnesium oxide compounds (Mg 2 ${{}_{2}}$ O/Mg 2 ${{}_{2}}$ O + ${{}^{+}}$ ) may play a role in silicate formation, but little vibrational reference data exist. As such, anharmonic spectroscopic data are computed for X Ë 1 Σ g + ${{{\tilde{\rm {X}}}}^1 {\rm{\Sigma }}_g^+ }$ Mg 2 ${{}_{2}}$ O, a Ë 1 Σ u + ${{{\tilde{\rm {a}}}}^1 {\rm{\Sigma }}_u^+ }$ Mg 2 ${{}_{2}}$ O, and X Ë 2 Σ g + ${{{\tilde{\rm {X}}}}^2 {\rm{\Sigma }}_g^+ }$ Mg 2 ${{}_{2}}$ O + ${{}^{+}}$ using quartic force fields (QFFs). Explicitly-correlated coupled-cluster QFFs for the neutral species perform well, implying that full multireference treatment may not be necessary for such systems if enough electron correlation is included. Equation-of-motion ionization potential (EOMIP) methods for X Ë 2 Σ g + ${{{\tilde{\rm {X}}}}^2 {\rm{\Sigma }}_g^+ }$ Mg 2 ${{}_{2}}$ O + ${{}^{+}}$ QFFs circumvent previous symmetry breaking issues even in explicitly-correlated coupled-cluster results, motivating the need for EOMIP treatments at minimum for such systems. All three species are found to have high-intensity vibrational frequencies. Even so, the highly intense frequency ( X Ë 1 Σ g + ${{{\tilde{\rm {X}}}}^1 {\rm{\Sigma }}_g^+ }$ Mg 2 ${{}_{2}}$ O 894.7â
cm-1/11.18â
µm; a Ë 1 Σ u + ${{{\tilde{\rm {a}}}}^1 {\rm{\Sigma }}_u^+ }$ Mg 2 ${{}_{2}}$ O 915.0â
cm-1/10.91â
µm) for either neutral state may be astronomically obscured by the polycyclic aromatic hydrocarbon 11.2â
µm band. Mg 2 ${{}_{2}}$ O + ${{}^{+}}$ may be less susceptible to such obfuscation, and its ν 1 ${{\nu }_{1}}$ intensity is computed to be a massive 4793â
km mol-1.
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Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
Chemphyschem
Asunto de la revista:
BIOFISICA
/
QUIMICA
Año:
2024
Tipo del documento:
Article
País de afiliación:
Estados Unidos