ROTATIONAL STRUCTURE OF THE B-X SYSTEM OF NA-3 FROM HIGH-RESOLUTION RESONANT 2-PHOTON IONIZATION SPECTROSCOPY

First investigations of the B(2)A'(1)-X(2)B(2) system of Na-3 at rotat ional resolution are reported. Using resonant two-photon ionization an d optical-optical double resonance spectroscopy, two vibronic bands we re assigned and rotationally analyzed. In the B state, the three sodiu m nuclei perform a nearly free pseudorotational motion in the moat of a pseudo-Jahn-Teller potential that is characterized by a vibronic ang ular momentum quantum number j. In states with j > 0, each rotational level is split by Coriolis interaction. Rotational and Coriolis coupli ng parameters were determined and are discussed in terms of the dynami cs of the vibronic coupling in this floppy molecule.