DFT study of molecular properties , potential energy surface and Stability of the dioxide of the group 12 M(O2): M=Zn, Cd and Hg

Two potential energy surfaces PESs in the lowest energy multiplicities triplet 3 A'' and singlet 1 A' for the dioxide of heavy metals of the group 12 Zn(O 2 ), Cd(O 2 ) and Hg(O 2 ) have been studied through DFT methods with the B3LYP functional. The core electrons of Zn (30 electrons), Cd (48 electrons) and Hg (60 electrons) are represented by pseudopotential ECP and the valences electrons are explicitly treated with the quasi-relativistic basis MWB and the full relativist basis AVTZ-PP. Both linear C ∞v and D ∞h or bent C s and cyclic C 2v structures of M(O 2 )have been considered in this work. The different pathways of dissociation and formation of M(O 2 ) and their dissociative limits M+O 2 and MO+O have been examined to discuss the stability of these molecules. Structural, spectroscopic and thermodynamic properties of stationary points are presented and compared with previous theoretical and experimental studies.