Energy and spectroscopic parameters of neutral and cations isomers of the C n H 2 (n = 2-6) families using high-level ab-initio approaches.

Autor: Díaz Soto LJ; Instituto de Química, Universidade Federal do Rio de Janeiro, Cidade Universitária, CT, Rio de Janeiro, Brazil., Oliveira RR; Instituto de Química, Universidade Federal do Rio de Janeiro, Cidade Universitária, CT, Rio de Janeiro, Brazil., Baptista L; Departamento de Química e Ambiental, Faculdade de Tecnologia, Universidade do Estado do Rio de Janeiro, Resende, Brazil., da Silveira EF; Departamento de Física, Pontifícia Universidade Católica do Rio de Janeiro, Rio de Janeiro, Brazil., Nascimento MAC; Instituto de Química, Universidade Federal do Rio de Janeiro, Cidade Universitária, CT, Rio de Janeiro, Brazil.
Jazyk: angličtina
Zdroj: Journal of computational chemistry [J Comput Chem] 2024 Aug 23. Date of Electronic Publication: 2024 Aug 23.
DOI: 10.1002/jcc.27485
Abstrakt: Cationic species, previously detected from ion-induced desorption of solid methane by plasma desorption mass spectrometry (PDMS), and neutral species, are investigated using high-level ab-initio approaches. From a set of 25 cationic and 26 neutral structures belonging to C n H 2 (n = 2-6) families, it was obtained the energy, rotational constants, harmonic vibrational frequency, charge distribution and excitation energies. The ZPVE-corrected energies, at CCSD(T)-F12; CCSD(T)-F12/RI/(cc-pVTZ-F12, cc-pVTZ-F12-CABS, cc-pVQZ/C) (n = 2-5) and CCSD(T)/cc-pVTZ (n = 6) levels, reveal that the topology of the most stable isomer vary with n and the charge. Out of 674 harmonic frequencies, those with maximum intensity are generally in the 3000-3500 cm -1 range. Analysis of 169 vertical transition energies calculated with the EOM-CCSD approach, suggest three C 6 H 2 species as potential carriers of the diffuse interstellar bands (DIB). Systematic comparison of properties between neutral and cationic species can assist in the structural description of complex matrices.
(© 2024 Wiley Periodicals LLC.)
Databáze: MEDLINE
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