Radiative transition probabilities between low-lying electronic states of N₂

This work mainly investigates the transition dipole moments (TDMs) and radiative transition probabilities of dipole-allowed transitions between the (Formula presented.), (Formula presented.), (Formula presented.), (Formula presented.), (Formula presented.), (Formula presented.), (Formula presented.), (Formula presented.), (Formula presented.) and (Formula presented.) states of N₂. Many of these transition properties are previously unknown. For completeness, another 14 electronic states that correlate to four lowest dissociation limits are also calculated. The potential energy curves (PECs) are calculated at the valence internally contracted multireference configuration-interaction (icMRCI) level of theory, along with the Davidson correction, the core-valence (CV) correction and the scalar relativistic correction, as well as the basis-set extrapolation. These corrections, especially the CV correction, greatly improve the accuracy of the PECs, as shown by the excellent agreement of the fitted spectroscopic parameters with the available experimental data. In order to verify the accuracy of transition properties, we calculate the Einstein coefficients of the extensively studied (Formula presented.) band transition systems and compute the radiative lifetimes of (Formula presented.) states, which are in good agreement with the experimental data. Similar accuracy can be assumed for the previously undetermined (Formula presented.) band transition systems. The large Einstein coefficients of these band systems can provide guidelines for observing such newly predicted band transitions in the appropriate spectroscopy experiments.