RT Journal Article
T1 Approximating correlation effects in multiconfigurational self-consistent field calculations of spin-spin coupling constants
A1 San Fabián, Jesús
A1 Díez, Enrique
A1 García de la Vega, José Manuel
A1 Suardíaz Delrío, Reynier
AB The multiconfigurational self-consistent field  MCSCF method in their approximations restricted and complete active spaces  RAS and CAS provides a theoretically accurate description of the coupling constants of a wide range of molecules. To obtain accurate results, however, very large basis sets and large configuration spaces must be used. Nuclear magnetic resonance coupling constants for the equilibrium geometry have been calculated for a series of small molecules using approximated correlation contributions. The four contributions to the coupling constants  Fermi contact, spin dipolar, orbital paramagnetic, and orbital diamagnetic have been calculated at the CAS and RAS MCSCF and second-order polarization propagator approximation levels using a large basis set. An additive model that considers the effect on the coupling constants from excitation of more than two electrons and from core-electron correlation is used to estimate the coupling constants. Compared with the experimental couplings, the best calculated values, which correspond to the MCSCF results, present a mean absolute error of 3.6 Hz and a maximum absolute deviation of 13.4 Hz. A detailed analysis of the different contributions and of the effects of the additive contributions on the coupling constants is carried out
PB American Institute of Physics
SN 0021-9606
YR 2008
FD 2008
LK https://hdl.handle.net/20.500.14352/92261
UL https://hdl.handle.net/20.500.14352/92261
LA eng
NO J. San Fabián, E. Díez, J. M. García de la Vega, R. Suardíaz; Approximating correlation effects in multiconfigurational self-consistent field calculations of spin-spin coupling constants. J. Chem. Phys. 28 February 2008; 128 (8): 084108. https://doi.org/10.1063/1.2834210
NO Ministerio de Ciencia, Innovación y Universidades (España)
NO Universidad Autónoma de Madrid
DS Docta Complutense
RD 8 abr 2025