Zeeman relaxation of MnH (X7Σ+) in collisions with 3He: Mechanism and comparison with experiment

We present a theoretical study of the Zeeman relaxation of the magnetically trappable lowest field seeking state of MnH (7Σ) in collisions with 3He. We analyze the collisional Zeeman transition mechanism as a function of the final diatomic state and its variation as a function of an applied magnetic field. We show that as a result of this mechanism the levels with ΔMj>2 give negligible contributions to the Zeemam relaxation cross section. We also compare our results to the experimental cross sections obtained from the buffer-gas cooling and magnetic trapping of this molecule and investigate the dependence of the Zeeman relaxation cross section on the accuracy of the three-body interaction at ultralow energies.