Spin polarization as an electronic cooperative effect

Nadia Ben Amor (1) , Camille Noûs (2) , Georges Trinquier (3) , Jean-Paul Malrieu (3)

1 GMO - Groupe THEO (LCPQ)
2 Laboratoire Cogitamus = Cogitamus Laboratory
3 SEM - Systèmes étendus et magnétisme (LCPQ)

The density matrix renormalization group in chemistry and molecular physics: Recent developments and new challenges The Journal of Chemical Physics 152, 040903 (2020); https://doi. ABSTRACT Taking as an example the simple CH 3 radical, this work demonstrates the cooperative character of the spin-polarization phenomenon of the closed-shell core in free radicals. Spin polarization of CH σ bonds is not additive here, as spin polarization of one bond enhances that of the next bond. This cooperativity is demonstrated by a series of configuration interaction calculations converging to the full valence limit and is rationalized by analytic developments. The same phenomenon is shown to take place in those diradicals where spin polarization plays a major role, as illustrated in square planar carbo-cyclobutadiene C 12 H 4. The treatment of cooperativity represents a challenge for usual post-Hatree-Fock methods. Published under license by AIP Publishing. https://doi.

Mots clés: Configuration interaction; Perturbation theory; Cooperative effect; Free radicals; Polarization; Electronic correlation; Transition state

Domaines: Chimie théorique et/ou physique

Nadia Ben Amor, Camille Noûs, Georges Trinquier, Jean-Paul Malrieu. Spin polarization as an electronic cooperative effect. Journal of Chemical Physics, 2020, 153 (4), pp.044118. ⟨10.1063/5.0011582⟩. ⟨hal-02958773⟩