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An algebraic alternative for the accurate simulation of CO 2 Raman spectra
Author(s) -
BermúdezMontaña Marisol,
Carvajal Miguel,
PérezBernal Francisco,
Lemus Renato
Publication year - 2020
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.5801
Subject(s) - raman spectroscopy , polarizability , anharmonicity , hamiltonian (control theory) , spectral line , fermi resonance , physics , algebraic number , molecule , molecular physics , chemistry , atomic physics , computational chemistry , quantum mechanics , mathematics , mathematical analysis , mathematical optimization
We present an accurate simulation of the Raman spectrum of the carbon dioxide molecule in the 1150–1500 cm −1 spectral range, comparing the results obtained using the three polyad schemes found in the literature of this molecule. The description of the molecule with the algebraic U 1 (2)× U (3)× U 2 (2) local model encompasses both stretching and bending degrees of freedom. A detailed analysis of the Hamiltonian interactions for the three polyad schemes provides fittings with root mean square deviations in the range 0.14–0.20 cm −1 , involving 19 parameters taking into account the 178 experimental term energies found in the literature. Using a limited subset of 9 experimental transition moments, we optimize 5 partial derivatives of the mean polarizability and simulate the Raman spectrum of CO 2 for the three polyad schemes. Comparing the calculated results with the experimental spectrum, we obtain an overall good agreement for the three polyads. However, an inspection in detail of the spectrum seems to show a slight preference for polyad P 212 albeit not due to the interaction characterizing the polyad but due to anharmonic effects and energy distribution. Finally, we assess the effect of the Fermi resonance over CO 2 Raman line intensities.