Infrared intensities of [Formula: see text]: a true challenge for DFT methods.

Autor: Richter WE; Department of Chemistry, Federal University of Technology - Paraná [UTFPR], 84.017-220, Ponta Grossa, PR, Brazil. richter@utfpr.edu.br., Duarte LJ; Institute of Chemistry, State University of Campinas [UNICAMP], 13.083-970, Campinas, SP, Brazil.
Jazyk: angličtina
Zdroj: Journal of molecular modeling [J Mol Model] 2022 Sep 06; Vol. 28 (10), pp. 301. Date of Electronic Publication: 2022 Sep 06.
DOI: 10.1007/s00894-022-05275-9
Abstrakt: Absolute infrared intensities of [Formula: see text] were evaluated with a great variety of DFT and ab initio methods and basis sets. It is shown that the intensities calculated by different levels of theory may not agree with each other even in the qualitative (weak/strong) sense. Geometrical parameters, as well as net atomic charges evaluated from multiple partition schemes, did not vary as much as the intensities and thus cannot explain the tremendous differences found for the latter. As there are no experimental estimates for the intensities to guide the theoretical evaluation, deciding on the best level of theory is reduced to comparisons between the different DFT methods and QCISD or CCSD, believed to be the best theoretical estimates in the set. The differences found among the various DFT methods suggest the development of new methods, instead of converging to a focal point, is rather diverging.
(© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)
Databáze: MEDLINE
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