Predissociation of the Na2 33Πg and other triplet states

The Na-2 3 (3) Pi(g) state adiabatically dissociates to the 3s+4p atomic limit. The 3 (3) Pi(g) levels below the 3s + 3d atomic limit have been observed by perturbation facilitated optical-optical double resonance (PFOODR) fluorescence excitation spectroscopy. Energy levels above the 3s + 3d atomic limit cannot be observed by detecting molecular fluorescence but are observable by detecting atomic 3d-->3p fluorescence. The 3 (3) Pi(g) state interacts with the 3s + 3d 2 (3) Pi(g) state. At lower energy this interaction is responsible for many perturbations between bound vibrational levels of these two states. Above the 3s + 3d limit, as a result of this interaction, the 3 (3) Pi(g) state is strongly predissociated and the linewidths of levels close to the 3s + 3d limit are about 22 cm(-1). The predissociation interaction is due to an avoided crossing between the adiabatic (2) (3) Pi(g) and 3 (3) Pi(g) states at R approximate to 2.85 Angstrom. Weak predissociation of the 4 (3) Sigma(g)(+) and 2 (3) Delta(g) states are also observed and discussed. (C) 1998 American Institute of Physics.