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Inclusion of hydrogen p orbitals in the semiempirical calculation of NMR parameters. I. Influence on the FPT INDO spin–spin coupling constants
Author(s) -
Facell J. C.,
Contreras R. H.
Publication year - 1980
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560180506
Subject(s) - geminal , atomic orbital , coupling constant , chemistry , fermi contact interaction , basis set , hydrogen , spin (aerodynamics) , proton , molecular orbital , molecule , computational chemistry , atomic physics , molecular physics , physics , quantum mechanics , density functional theory , thermodynamics , hyperfine structure , electron , stereochemistry , organic chemistry
Hydrogen 2 p orbitals have been introduced into the basis set to calculate the Fermi contact term of spin–spin coupling constants using the FPT INDO method. Different coupling constants show different sensitivity to these hydrogen polarization functions. Some improvements are found for molecules containing N or F. Calculations of proton‐proton geminal coupling constants give more negative results than those of FPT INDO , yielding a better agreement with experimental values. The π‐transmission mechanism is notably exaggerated.