Fine and hyperfine structure of the triplet states 1(3)Sigma(u)(+) and 1(3)Sigma(g)(+) of the Na-2 molecule

The 1(3) Sigma(g)(+) <-- 1(3) Sigma(u)(+) absorption spectrum of Na-2 has been measured with sub-Doppler resolution in a collimated cold argon beam seeded with sodium vapor, using resonant two-photon ionization with a cw single mode Ti-sapphire laser and a cw argon laser. The spectrally resolved fine and hyperfine structure of the rotational lines allowed the determination of the spin-spin interaction constants lambda '' = - 1294 MHz, lambda' = -529 MHz, the spin-rotation constants gamma '' = 42 MHz, gamma' = 2.6 MHz and the Fermi contact constants b '' = 293 MHz, b' = 223 MHz. All the molecular constants of both electronic states obtained from this and from former work are compiled and compared with theoretical values.