Quantum-interference effects in the o ¹Π_u(v=1) ∼ b¹Π_u(v=9) Rydberg-valence complex of molecular nitrogen

Two distinct high-resolution experimental techniques, 1 [image omitted] UV laser-based ionization spectroscopy and synchrotron-based XUV photoabsorption spectroscopy, have been used to study the o[image omitted] Rydberg-valence complex of 14N2, providing new and detailed information on the perturbed rotational structures, oscillator strengths, and predissociation linewidths. Ionization spectra probing the b[image omitted] state of 14N2, which crosses o1u(v=1) between J = 24 and J = 25, and the o1u(v=1), b,1u(v=9), and b[image omitted] states of 14N15N, have also been recorded. In the case of 14N2, rotational and deperturbation analyses correct previous misassignments for the low-J levels of o(v=1) and b(v=9). In addition, a two-level quantum-mechanical interference effect has been found between the o-X(1, 0) and b-X(9, 0) transition amplitudes which is totally destructive for the lower-energy levels just above the level crossing, making it impossible to observe transitions to b(v=9,J=6). A similar interference effect is found to affect the o(v=1) and b(v=9) predissociation linewidths, but, in this case, a small non-interfering component of the b(v=9) linewidth is indicated, attributed to an additional spin-orbit predissociation by the repulsive [image omitted] state.