THEORETICAL SEARCH FOR SMALL LINEAR DOUBLY CHARGED ANIONS

The electronic stabilities of linear diatomic C(2)2-, BN2-, BP2-, BeO2-, BeS2-, MgO2-, MgS2-, O(2)2-, SO2-, and S(2)2-; triatomic NCN2-, SBN2-, OBeO2-, SBeC2-, SBeO2-, OMgO2-, SMgS2-, PCP2-, and SCC2-; tetratomic OCCO2- and SCCS2- and pentatomic Be2O32-, Be2S32-, Mg2O32-, and Mg2S32- dianions were studied at the Hartree-Fock level with Gaussian basis sets including diffuse and polarization functions, as well as at the second-order Moller-Plesset level. Vertical first detachment energies of several dianions were also calculated at the fourth-order Moller-Plesset level. All diatomic, triatomic, and tetratomic dianions were found to be unstable to electron loss. The pentatomic Mg2S32- dianion is predicted to be stable to electron loss with an electron detachment energy of 0.2 eV. This species is likely to be the smallest electronically stable linear dianion.