Abstract

The nitrosylium ion was observed very recently for the first time in the interstellar medium. We compute the rotationally inelastic cross-sections and rate coefficients for the two lowest vibrational levels of NO+ colliding with He. The most favoured transitions are found to correspond to even Delta j. We also compare the rank order of the magnitudes of the rotational transition rate coefficients for each of the two lowest vibrational levels of NO+ and find that they can differ slightly for a few temperatures.