ملخص: The 3D Feynman-Kleinert method is applied to the potential V(r) = -[alpha]/r + [Sigma]n = 1N[alpha]nrn. The approximate free energies which tend to the exact ground state energies in the low-temperature limit are obtained for some particular cases of the potential. They are in good agreement with those given by Varshni and by Bessis et al.

لغة: إنجليزية