AlF-He cold collision: Rotational quenching and buffer gas cooling efficiency

We present a study of the state-to-state scattering cross-sections pertaining to the AlF-He collisions at cold temperatures (E > 1mK) with AlF being in its vibrational ground state. The relevant cross sections are obtained via a coupled channel approach fed with a novel two-dimensional ab initio potential energy surface. The coupled channel results for the elastic cross sections are contrasted with a single-channel calculation as well as a semi-classical approach that is commonly used to estimate a molecule's cooling and diffusion properties in a buffer gas. Consequently, we evaluate the role of shape resonances at energies relevant to buffer gas cooling experiments. In addition, relaxation rates for the relevant rotational states of AlF are also calculated.