Article Dans Une Revue Journal of Physical Chemistry A Année : 2024

Rovibrational line lists of triplet and singlet methylene

Résumé

Methylene molecule (CH2) is a short-lived radical with lacking data on its spectral line intensities.

Although the lifetime of CH2 is extremely short under the Earth's conditions, it exists in a free form in interstellar media. CH2 is an important intermediate species in chemical reactions associated with the formation and destruction of complex hydrocarbons. We present the first rovibrational line lists of CH2 in its ground triplet and first excited singlet electronic. To this end, our previously developed accurate ab initio potential energy surface (PES) was used for the ground electronic triplet state [Egorov et al. J. Comp. Chem. 2024. V.

45.

(2). P. 83] while a new PES for the singlet state was constructed in this work using the single-reference coupled cluster approach [CCSD(T)] combined with the extrapolation to the complete basis set (CBS) limit based on the correlation-consistent orbital basis sets with the core-valence electron correlation [aug-cc-pCVXZ, X = T, Q, 5, and 6]. In addition, the contributions to the correlation energy from highly-excited Slater determinants [CC(n), n=3-5] were included as well as the scalar relativistic effects and DBOC. The most accurate description of the infrared band origins of singlet CH2 was thus achieved for the energy range where the impact of the nonadiabatic coupling due to the Renner-Teller effect can be neglected. To obtain the probabilities of the rovibrational transitions, new ab initio DMSs were constructed both for the triplet and singlet CH2 using the CCSD(T)/aug-cc-pCVQZ approach. Finally, the absorption spectra of triplet and singlet methylene were predicted from the variationally computed line lists.

Fichier principal
Vignette du fichier
ch2_line_lists.pdf (1.57 Mo) Télécharger le fichier
Origine Fichiers produits par l'(les) auteur(s)
Licence

Dates et versions

hal-04780391 , version 1 (13-11-2024)

Licence

Identifiants

Citer

Oleg Egorov, Michael M. Rey, Dominika Viglaska, Andrei Nikitin. Rovibrational line lists of triplet and singlet methylene. Journal of Physical Chemistry A, 2024, 128 (33), pp.6960-6971. ⟨10.1021/acs.jpca.4c04205⟩. ⟨hal-04780391⟩
142 Consultations
194 Téléchargements

Altmetric

Partager

  • More