Ground state of Co(N-2)(+)

A combined experimental (ion/molecule reactions in a Fourier-transform ion cycloctron resonance mass spectrometer) and theoretical (correlated ab initio calculations using coupled-cluster and multireference configuration interaction wave functions) approach characterizes the electronic ground state of the cationic cobalt-dinitrogen complex Co(N-2)(+) as a linear species ((3) Delta) with a 0 K binding energy of 23.0 +/- 1.7 kcal/mol. Recent speculation [J. Phys. Chern. 1995, 99, 1068] on a T-shaped ground state geometry of Co(N-2)+ is repudiated on the basis of the measured binding energy as well as the calculated potential energy surface for rotation of N-2 around its center of mass in the electrostatic potential of the Co+ cation.