Superposition-state N2+ produced in the intermolecular charge transfer from low-energy Ar+ to N2

Molecular electronic or vibrational states can be superimposed temporarily in an extremely short laser pulse, and the superposition-state transients formed therein receive much attention, owing to the extensive interest in molecular fundamentals and the potential applications in quantum information processing. Using the crossed-beam ion velocity map imaging technique, we disentangle two distinctly different pathways leading to the forward-scattered N-2(+) yields in the large impact-parameter charge transfer from low-energy Ar+ to N-2. Besides the ground-state (X-2 Sigma(+)(g)) N-2(+) produced in the energy-resonant charge transfer, a few slower N-2(+) ions are proposed to be in the superpositions of the X-2 Sigma(+)(g)-A(2)Pi(u) and A(2)Pi(u)-B-2 Sigma(+)(u) states on the basis of the accidental degeneracy or energetic closeness of the vibrational states around the X-2 Sigma(+)(g)-A(2)Pi(u) and A(2)Pi(u)-B-2 Sigma(+)(u) crossings in the non-Franck-Condon region. This finding potentially shows a brand-new way to prepare the superposition-state molecular ion.