Cooling and quenching of 24MgH+(X 1Σ+) by 4He(1S) in a Coulomb trap: A quantum study of the dynamics

The quantum dynamics of the rotational quenching of the 24MgH+(X 1Σ+) molecular cation interacting with 4He(1S) as a buffer gas, at relative temperatures ranging from 1 K down to millikelvins, is described by accurate close coupling scattering calculations on an ab initio potential energy surface. The efficiency of the process is quantitatively analyzed by employing the ab initio quenching rates and cross sections and effective decay rate values are obtained from simple unimolecular kinetics over a broad range of trap conditions.