title: Magnetic interactions in phenyl-bridged nitroxide diradicals: conformational effects by multireference and broken symmetry DFT approaches.
abstract: In the present paper we report the key results of a comprehensive computational study aimed at investigating the dependence of the singlet-triplet energy gap in phenyl-bridged bis-nitroxide diradicals, on the basis set and on soft structural parameters like torsion and pyramidalization. We have compared the BS-DFT technique with the post-Hartree-Fock DDCI2 multireference approach. With this latter method we have also studied the different role that sigma and pi core and virtual orbitals have in the resulting singlet-triplet energy gap.The results obtained represent one step forward in the definition of a protocol for an efficient and reliable computation of spin-spin coupling in diradical systems.
authors.affiliation: Scuola Normale Superiore, Piazza dei Cavalieri, I-56126 Pisa, Italy. vincenzo.barone@sns.it
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Barone
authors.forename: Ivo
authors.initials: I
authors.lastname: Cacelli
authors.forename: Paola
authors.initials: P
authors.lastname: Cimino
authors.forename: Alessandro
authors.initials: A
authors.lastname: Ferretti
authors.forename: Susanna
authors.initials: S
authors.lastname: Monti
authors.forename: Giacomo
authors.initials: G
authors.lastname: Prampolini
mesh_terms: D008280:Magnetics; D008958:Models, Molecular; D008968:Molecular Conformation; D009589:Nitrogen Oxides / Q000737:chemistry*; D011789:Quantum Theory; D012015:Reference Standards; D013816:Thermodynamics
chemical_list: D009589:Nitrogen Oxides; C039900:nitroxyl