Excited vibrational-states near dissociation in weakly bound triatomic systems

The vibrational motion of a weakly bound M3 complex is investigated using hyperspherical coordinates and an adiabatic separation of the radial and angular motions within the molecule. It is shown that the vibrational energy levels near dissociation correlate to an M atom orbiting about a rotating M2 core. Application is made to the neon trimer assuming an approximate pairwise additive potential