The calculation of the ground state energy of weakly bound van der waals trimers using the method of hyperspherical harmonics. II. Non-adiabatic corrections

Abstract

Accurate calculations of the ground state energy levels of the three-particle van der Waals complexes Ne3 and (H2)3 are presented. The method uses a hyperspherical coordinate system and is based on a Born-Oppenheimer separation of the hyper-radial and angular degrees of freedom. Non-adiabatic effects are included by Ryleigh-Schrödinger perturbation theory. A new accurate method based on Brillouin-Wigner perturbation theory is also presented. © 1985.