INTEGER QUANTIZATION OF THE PSEUDOROTATIONAL MOTION IN NA3B

Fractional quantization of vibronic states of a molecule can be expected when two electronic potential energy surfaces experience a conical intersection and the vibrational and electronic wave functions change sign under 2 rotation in the vibrational coordinates. The B state of Na3 was believed to exhibit this behavior. High resolution spectroscopy of the B-X system of Na3 is reported which is reassigned as B2A1-X2B2. The analysis of rotational structure and Coriolis interaction shows that the vibronic angular momentum j is integer quantized, in contrast to previous interpretations. Therefore, the B state of Na3 can no longer be considered as an example of Berry's geometrical phase in a molecule. © 1994 The American Physical Society.