Theoretical studies on the structures and isomerization of C3N+

DFT and coupled-cluster (single-point) calculations are performed on C3N+ isomers and their interconversion transition states. It is shown that two isomerization pathways exist between the lowest CCCN+ and the second low-lying CCNC+, while the rhomboidal structure with C–C cross bonding and the CNC three-membered ring structure with exocyclic C–C bonding are respective stable intermediates along the two pathways. The possible formation of the isomers of C3N+ presented in this Letter may provide reasonable interpretation of the experimental facts in which the C3N+ isomers are involved.