HIGH RESOLUTION SPECTROSCOPY OF THE $Na_{3}$ B-X SYSTEM

Abstract

[1] G. Delacretaz, E.R. Grant, R.L. Whetten, L. Woeste, J.W. Zwanziger, Phys.Rev.Lett. 56, 2598 (1986) [2] W.Meyer: Kaiserslautern; private communicationAuthor Institution: Department of Physics, The Pennsylvania State UniversityCw RTPI spectroscopy of $Na_{3}$ has been performed in a supersonic molecular beam. The spectra of several vibraonic bands of the B-X transition were recorded at rotational resolution. As result of previous experiments at vibrational resolution, these bands had been interpreted in terms of the dynamic Jahn-Teller effect [1]. In this picture, the B-state vibronic levels have to be described by half-odd quantum numbers j for the vibronic angular momentum. Our rotationally resolved spectra show distinct differences between the lowest radial vibration $v^{+}=0$ in the B-state and all excited vibrational states (v^{\prime}$\geq$1). This indicates a low localization energy and the excited vibrational states can be approximated by a symmetric rotor with a bond angle of $60^{\circ}$. Depending on the degeneracy of the vibronic state j, different coriolis coupling terms have been taken into account in model calculations in which the ground state was approximated as asymmetric rotor [2]. For a number of rotational lines 00DR spectra were recorded whcih helped to identify the different branches