AbstractThe B2A'1 ‐ X2B2 system of Na3 has been investigated at rotational resolution by using resonant two photon ionization and optical‐optical double resonance spectroscopy. A number of vibronic bands were assigned and rotationally analyzed. In states which are excited by at least one quantum in the linear distortion mode, the three sodium nuclei perform a free pseudorotational motion in the moat of a pseudo‐Jahn‐Teller potential. Structure and dynamics of this floppy molecule are discussed on the basis of the measured rotational and Coriolis coupling parameters.