  Peculiarities of the intermolecular rovibrational quantum dynamics of the
methane-argon complex are studied using a new, ab initio potential energy
surface [Y. N. Kalugina, S. E. Lokshtanov, V. N. Cherepanov, and A. A. Vigasin,
J. Chem. Phys. 144, 054304 (2016)], variational rovibrational computations, and
detailed symmetry considerations within the molecular symmetry group of this
floppy complex as well as within the point groups corresponding to the local
minimum structures. The computed (ro)vibrational states up to and beyond the
dissociation asymptote are characterized using two limiting models: the rigidly
rotating molecule's model and the coupled-rotor model of the rigidly rotating
methane and an argon atom orbiting around it.
