Electronic Structures of Ions ofm-Phenylenebis (Phenylmethylene). II - The Electron Correlation Effects -

Abstract

m -Phenylenebis (phenylmethylene) ( m -PBPM) has the quintet ground state in the neutral state, due to the dynamic spin polarization (DSP) in the π system and exchange interaction between n and π electrons on carbenes. The experimental results by the ESR show that both monocation and monoanion of m -PBPM have the quartet ground state. We calculate the electronic structures of the ions with the unrestricted Hartree-Fock (UHF) and resonating Hartree-Fock (Res HF) methods. We use the model that includes only n and π electrons developed in a previous paper. The broken spatial and spin symmetries of the UHF solutions are restored by the Res HF calculations of electron correlation effects. In the UHF approximation, the doped charge is always localized on a carbene and the adjacent phenylenes as a spin density wave (SDW) polaron. The n spins on the right and left carbenes are parallel and antiparallel in the quartet and doublet states, respectively. Due to this fact, the stabilization by the quantum motion of th...