Collisional excitation of MgO by He

Abstract

Using a well-established ab initio methodology to generate the potential energy surface of the MgO–He interacting system and a quantum close-coupling treatment of nuclear motion, we give the rotational (de-)excitation cross-sections and the collision rate coefficients for the first 16 rotational levels of the MgO molecule and He for temperatures ranging from 10 up to 300 K. A clear propensity rule in favour of Δj = 1 rotational transitions is observed. These data are compared with previous works on astrophysical oxygen-bearing diatomic species. This work should be useful for the eventual detection of the key metal-oxide MgO molecule in the circumstellar and interstellar media with current and future high-resolution telescopes.