Heavy rarehyphen;gas trimers and tetramers: Testing ground for fewhyphen;body techniques in chemical physics

摘要

The groundhyphen;state energies of systems of three and four identical heavy rarehyphen;gas atoms, treated as spinless bosons and assumed to interact via pairwise Morse potentials, are calculated using five different methods. Selfhyphen;bound trimers and tetramers are found in every case with upper and lower bound formulas yielding energies which are extremely close. For these nearhyphen;classical and massive systems, the Faddeevndash;UPE method is decidedly poor. On the other hand, the simple generalization of Bruchndash;Sawadarsquo;s upper bound is particularly effective. The plight of Faddeevndash;UPE here implies that great caution must be exercised in using the unitary pole expansion in chemical physics. ATMS is excellent and appears the method of choice for boundhyphen;state problems.