Optical observation of the C, 3sσgF3, and 3pπuG3 Π3u states of N2

High-resolution laser-based one extreme-ultraviolet (EUV)+one UV two-photon ionization spectroscopy and EUV photoabsorption spectroscopy have been employed to study spin-forbidden (3)Pi(u)-X (1)Sigma(g) (+)(v,0) transitions in (14)N(2) and (15)N(2). Levels of the C (3)Pi(u) valence and 3ssigma(g)F(3) and 3ppi(u)G(3) (3)Pi(u) Rydberg states are characterized, either through their direct optical observation, or, indirectly, through their perturbative effects on the (1)Pi(u) and (1)Sigma(u) (+) states, which are accessible in dipole-allowed transitions. Optical observation of the G(3)-X(0,0) and (1,0) transitions is reported for the first time, together with evidence for six new vibrational levels of the C state. Following the recent observation of the F(3)-X(0,0) transition at rotational resolution [J. P. Sprengers et al., J. Chem. Phys. 123, 144315 (2005)], the F(3)(v=1) level is found to be responsible for a local perturbation in the rotational predissociation pattern of the b(') (1)Sigma(u) (+)(v=4) state. Despite their somewhat fragmentary nature, these new observations provide a valuable database on the (3)Pi(u) states of N(2) and their interactions which will help elucidate the predissociation mechanisms for the nitrogen molecule.