Reactions of ions in excited electronic states: (CO+⋅) *+CO→C2O+⋅+CO

The formation of C2O+⋅ ions from electronically excited CO+⋅ ions has been studied in an ion cyclotron resonance (ICR) spectrometer. By analysis of the data it was possible to determine the rate constant for formation of C2O+⋅ to be k3⩽ (8.5±1.5) ×10−10 cm3 sec−1⋅molecule−1, the lifetime of the precursor CO+⋅ excited state to be k4−1⩾10−2 sec and the ratio of active CO+⋅ excited states to the remainder of the CO+⋅ formed in the electron beam to be k2/k1⩽3.8±0.4×10−3. A comparison is made between the CO results presented here and those for the isoelectronic N2 system reported earlier [J. Chem. Phys. 61, 4394 (1974)]. It is suggested that a barrier to N4+⋅ formation from electronically excited N2+⋅ quartet ions may exist in the nitrogen system from spin correlation rule considerations. Reasons for the existence of the barrier in the N2 system and the apparent absence of such a barrier in CO are suggested. The heat of formation of C2O+⋅ is approximately determined to be ΔHf(C2O+⋅) =392±10 kcal/mole.