M dependence in the analysis of NH3–He microwave double resonance experiments

New close-coupled calculations of laboratory-frame, m-dependent cross sections for rotational excitation in NH3–He collisions are used to examine the validity of using degeneracy averaged values in the analysis of four-level double resonance experiments. It is found that the proper use of m-dependent cross sections and absorption probabilities produces only minor changes in the calculated ΔI/I and does not, therefore, resolve the discrepancies between theoretical and experimental values that were noted in previous studies.