Weakly bound valence states of 2_g symmetry, correlating with the I(² P _3/2) + I(² P _3/2) (aa) and I(² P _3/2) + I(² P _1/2) (ab) dissociation limits, as well as (ab) state, were studied using vibrationally resolved luminescence spectra corresponding to transitions from δ2_u(³ P ₂) and g (³ P ₁) ion-pair states, in molecular iodine, respectively, populated using a three-step three-color laser excitation scheme. Spectroscopic constants and potential energy curves of the valence states are determined for the first time. Dipole moment functions of δ2_u → 2_g(aa, ab) and g → (ab) transitions are found to exponentially decrease.