Effects of three-body (Axilrod-Teller) forces on the classical and quantum behavior of rare-gas trimers

Abstract

We have studied the structure and dynamics of nonrotating rare-gas trimers bound by a potential that combines two-body Lennard-Jones interactions and three-body Axilrod-Teller (triple dipole) interactions. Both classical and quantum trimers are examined. We investigate the onset and development of chaotic dynamics in the classical clusters by computing the Liapunov exponents associated with various phase space trajectories. In our studies of the quantum clusters, we examine the structure of the vibrational eigenstates, the statistical properties of the distribution of energy levels, and the average cluster structure at finite temperatures. Both avenues of research are principally aimed at understanding the effect of the three-body term on the clusters' behavior. We find that the three-body term gives rise to an integrable or nearly integrable component of phase space that is associated with the clusters' linear configuration and that manifests itself in both the classical and quantum properties of the trimers. The finite temperature structures predicted for quantum Ne${}_{3}$ clusters suggest that over the range of parameters considered here, these clusters are sufficiently delocalized that properties associated with the linear configuration should be readily observable, even at very low temperatures.