Theoretical Characterization of C₆N, C₆N⁻, and C₆N⁺

Abstract

This work emphasizes the stability of C 6 N linear carbon chains and carbon clusters containing three-body rings. C 6 N possesses at least 44 neutral isomers and 38 and 35 isomers with a negative or a positive charge. The lowest-energy structures, which can be candidates for laboratory and astrophysical detection, were studied with RCCSD(T)-F12 and MRCI/CASSCF, specifying properties for various electronic states. Neutral C 6 N displays two prominent equilibrium structures, a nitrogen-terminated linear form (X 2 Π) and a C 2v form (X 2 B 2 ) containing a three-carbon ring. They are separated by 0.21 eV. For the linear one, Renner-Teller and spin-orbit effects are expected. Its equilibrium spin-orbit constant |A so,e |was predicted to be 29.09 cm Below the electron affinity of the most stable isomer (EA=−3.42 eV), the linear anion displays three probably existing electronic states. Detectability is discussed in terms of the symmetry and spin multiplicity of the ground electronic states.