Zero field splitting parameters of diradicals and the elusive case of tetramethyleneethane

Abstract

We show that the semiempirical Austin Model 1/CI method provides good theoretical estimates of the zero field splitting (ZFS) parameters of organic diradicals. The elusive case of the tetramethyleneethane (TME) diradical is analyzed and it is found that the inclusion of sufficient CI leads to a triplet ground state at some twisted geometries. The computed ZFS values of TME at these geometries are compared with experimental data. © 1996 Elsevier Science B.V. All rights reserved.