The potential energy curve for Na-2 in the a (3)Sigma(u)(+) state is characterized by the R-e and D-e parameters which are found to be equal to 5.192 Angstrom and 177.7 cm(-1), respectively, at the coupled cluster level of theory with single, double, and noniterative triple excitations. It is argued that the theoretical value of R-e may be more accurate than that extracted from the experimental data [Friedman-Hill and Field, J. Chem. Phys. 96, 2444 (1992)].