Artículo
The role of the magnetic orbitals in the calculation of the magnetic coupling constants from multireference perturbation theory methods
Autor/es | Angeli, Celestino
Jiménez Calzado, Carmen |
Departamento | Universidad de Sevilla. Departamento de Química Física |
Fecha de publicación | 2012 |
Fecha de depósito | 2016-10-28 |
Publicado en |
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Resumen | The use of multireference perturbation theory (MRPT) for the calculation of the magnetic coupling
in binuclear complexes has shown to give poor results if applied on a minimal active space complete
active space self-consistent ... The use of multireference perturbation theory (MRPT) for the calculation of the magnetic coupling in binuclear complexes has shown to give poor results if applied on a minimal active space complete active space self-consistent field (CASSCF) wavefunction. In this work, we identify the origin of this problem in the starting CASSCF orbitals, which are exceedingly localized on the metal atoms. Focusing on the case of antiferromagnetic systems, it is shown that the form of the active orbitals has a dramatic effect on the relative description of the neutral and ionic structures. Finally, a simple and computational inexpensive strategy is proposed for the calculation of a set of magnetic orbitals describing in a more balanced way the neutral and ionic structures. The use of these orbitals, instead the CASSCF ones, in minimal active space MRPT2 calculations leads to a marked improvement of the J values, which become in reasonable agreement with those obtained with the expensive high level difference dedicated configuration interaction approach and with the experimental values |
Cita | Angeli, C. y Jiménez Calzado, C. (2012). The role of the magnetic orbitals in the calculation of the magnetic coupling constants from multireference perturbation theory methods. Journal of Chemical Physics, 137 (3), 1-9. |
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