Electronic states and potential energy curves of PI2 and PI2+

Spectroscopic constants and bending potential energy curves of nine electronic states of PI2 and three states of PI2+ have been determined by applying the complete active space self-consistent field (CASSCF) followed by multi-reference singles and doubles configuration interaction (MRSDCI) methods that included up to 1.2 million configurations. Our computations predict spectroscopic data of yet to be observed electronic states of PI2 and PI2+. The IP-I dissociation energy and the De of the diatomic PI have been calculated.