LAUSR

Abstract We present a theoretical characterization of the cation iodocarbyne, CI+, using a correlated theoretical approach (SA-CASSCF/MRCI) to describe a manifold of singlet, triplet, and quintet electronic states. Reliable potential energy curves were constructed for both Λ +S and relativistic Ω states. Spin-orbit couplings strongly affect the energetic profile of the Λ +S representation. Spectroscopic parameters were calculated, and effects of core-valence correlation investigated. The transition dipole moment functions for the 11 3 Π 0 + → X1 1 Σ 0 + + and 13 3 Π 1 → X1 1 Σ 0 + + states were evaluated and the corresponding radiative lifetimes obtained. Comparisons with other halocarbynes can now help understanding trends in properties in this class of molecules.