Spin-spin coupling in 3b2 state of oxyallyl - A comparative study with trimethylenemethane

Internal splittings in the spectra are due to quantized angular momentum field of the molecule or atom, which couples through spin-spin and spin-orbit operators. These operators are subjected to recently observed close lying states of oxyallyl biradical and compared with the iso-electronic structure trimethylenemethane. With the multiconfigurational treatment of spin-spin coupling operator we predict reversal of the splitting parameter Dss of oxyallyl with reference to isoelectronic TMM spectra.