Weakly bound triatomic 4He2 3He and 3He2 4He molecules

The bound rotational excited states of weakly bound (He2He)-He-4-He-3 and (He2He)-He-3-He-4 molecules have been searched for. Including pair interaction between helium atoms, we solved the Schrodinger equation for the triatomic systems with hyperspherical coordinates in the adiabatic approximation. The resulting potential curves are mostly repulsive for nonzero angular momenta. We conclude that no bound rotational excited states exist in both (He2He)-He-4-He-3 and (He2He)-He-3-He-4 molecules. The stability of the systems depends sensitively on the quantum symmetry and the masses of the particles. (C) 2004 Wiley Periodicals, Inc.