Rydberg states and new resonant states of the imidogen molecule NH: pathways for nitrogen release

Neutral resonant states of molecules play a very important role in the dissociation dynamics and other electronic processes that occur <i>via</i> intermediate capture into these states. With the goal of identifying resonant states and corresponding autoionization widths of the imidogen molecule NH as a function of internuclear distance, we have performed detailed <i>R</i>-matrix calculations on the e + NH⁺ system. In a previous work, we had identified bound states of NH and Feshbach resonances in the e + NH⁺ system at a single geometry, namely the NH⁺ equilibrium <i>R</i>_e = 2.0205<i>a</i>₀. Here we present a much more detailed work by repeating the calculation on over 60 internuclear distances to obtain the corresponding potential energy curves. The bound states for nine symmetries have been detailed many of which, particularly the singlet states, were never studied before. Several resonant states of different symmetries, which were unknown until now, have been systematically identified and their widths are calculated in the present work, which proved much more challenging due to the presence of many avoided crossings. It is hoped that the bound and the new resonant states obtained here will open up other molecular dynamics studies, since for several dissociative processes, although experimental data existed for more than a decade, these are still uncorroborated due to the absence of molecular data, and hence subsequent theoretical calculations.