3d electron delocalization studied by ortho- to para-positronium conversion reactions

Abstract

The ortho- to para-positronium conversion reactions promoted by the paramagnetic complexes formed by ethylenediaminetetraacetic acid (H₄EDTA) with Mn^II, Fe^II Co^II, Ni^II ions have been studied at various temperatures. The results are discussed together with those previously obtained for the Cr^III and Cu^II complexes with H₄EDTA. It was found that the rate constants, k_CR, are larger for complexes in which spin–orbit coupling occurs and for which the 3d inter-electronic repulsion parameter attains smaller values. These findings give further support to our proposal that the o-Ps to p-Ps conversion reaction may be used to investigate electron delocalization in paramagnetic 3d complexes.