Further results on the relationship between the rate constants of o-Ps into p-Ps conversion and the electron delocalization in 3d complexes

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