Rotational dependence of turning point surfaces and vibrational frequencies for Lennard-Jones argon clusters

The coupling of rotational and vibrational motions for small clusters of argon atoms modelled in terms of pairwise additive Lennard-Jones interactions is explored by the construction of angular momentum dependent turning point surfaces and by the evaluation of angular momentum dependent harmonic vibrational frequencies. The clusters considered include the trimer Ar 3 and the tetramer Ar 4 . Insights are obtained into the transition from chaotic to non-chaotic motion as the rotational angular momentum is increased at fixed total energy.