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dc.contributor.author
Zarycz, Maria Natalia Cristina
dc.contributor.author
Aucar, Gustavo Adolfo
dc.date.available
2019-06-14T19:30:10Z
dc.date.issued
2012-05
dc.identifier.citation
Zarycz, Maria Natalia Cristina; Aucar, Gustavo Adolfo; The analysis of NMR J-couplings of saturated and unsaturated compounds by the localized second order polarization propagator approach method; American Institute of Physics; Journal of Chemical Physics; 136; 17; 5-2012; 1-10; 174115
dc.identifier.issn
0021-9606
dc.identifier.uri
http://hdl.handle.net/11336/78379
dc.description.abstract
Calculations of NMR J-coupling with polarization propagators are not invariant under unitary transformations at second order level of approach, second order polarization propagator approach (SOPPA). They are only invariant at first order or random phase level of approach (RPA). We performed “localized” SOPPA (Loc-SOPPA), calculations of J-couplings applying two different schemes for the localization of molecular orbitals(LMO): Foster-Boys and Pipek-Mezey. We show here that results of such Loc-SOPPA calculations are different though not much: they are less than 6% different in the worst case. Therefore it is possible to apply them with confidence in the analysis of the transmission of different coupling mechanisms within the molecule. We are able now to get reliable information on what LMOs are the most important (and so which are not important) for a given J-coupling in a molecule. This information can then be used for selecting which are the paths that should be described with the highest possible accuracy for that J-coupling calculation. A few unsaturated compounds are analyzed: ethene, trans-difluoroethene or DiF-ethene, and imine. It is shown that different lone pairs (of pz or px/y type) are responsible for the vicinal F-F J-coupling in DiF-ethene; and also the fact that the main LP contributor is not the same for the fermi contact and the spin-dipolar mechanisms.We also studied phosphorous containing compounds such as phosphine and cis-propylene phosphine. In both cases the analysis of the main LMO contributing to one-bond P-H coupling and through-space P-C coupling were performed. The above mentioned unsaturated molecular systems have quasiinstability problems that arise at RPA level of approach. We show here that they are mostly originated in the antibonding π* LMO, corresponding to the C=C or C=N double bonds. We performed the analysis of the origin of quasiinstabilities for the SD mechanism. The contribution of each kind of excitation terms to SOPPA calculations were considered, meaning the main contributions by single and double excitations. It is shown that one can get more than 97% of the total electron correlation contribution when including terms that mainly contain single excitations (though double-excitation matrix elements should still be calculated).
dc.format
application/pdf
dc.language.iso
eng
dc.publisher
American Institute of Physics
dc.rights
info:eu-repo/semantics/openAccess
dc.rights.uri
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.subject
Nmr
dc.subject
Polarization Propagator
dc.subject
Loc-Soppa
dc.subject
Localized Orbitals
dc.subject.classification
Física Atómica, Molecular y Química
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Ciencias Físicas
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CIENCIAS NATURALES Y EXACTAS
dc.title
The analysis of NMR J-couplings of saturated and unsaturated compounds by the localized second order polarization propagator approach method
dc.type
info:eu-repo/semantics/article
dc.type
info:ar-repo/semantics/artículo
dc.type
info:eu-repo/semantics/publishedVersion
dc.date.updated
2019-05-14T17:48:34Z
dc.journal.volume
136
dc.journal.number
17
dc.journal.pagination
1-10; 174115
dc.journal.pais
Estados Unidos
dc.description.fil
Fil: Zarycz, Maria Natalia Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Modelado e Innovación Tecnológica. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Instituto de Modelado e Innovación Tecnológica; Argentina
dc.description.fil
Fil: Aucar, Gustavo Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Modelado e Innovación Tecnológica. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Instituto de Modelado e Innovación Tecnológica; Argentina
dc.journal.title
Journal of Chemical Physics
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/doi/https://doi.org/10.1063/1.3697844
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/url/https://aip.scitation.org/doi/10.1063/1.3697844
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