The Cs2 (3) 1Πu electronic state pumped by Ar+ laser lines.

The fluorescence spectra of the two electronic systems (3) 1Πu→X 1∑g appearing in the visible range and (3) 1Πu→(2) 1∑g in the near infrared has been observed using an argon ion laser to excite Cs2 molecules. Fluorescence lines were accurately measured with a high resolution Fourier transform interferometer. Accurate molecular constants and potential energy curves have been determined for the (3) 1Πu electronic state. The main constants are as follows: Te(cm-1) =20 684.669; we(cm-1) =30.398; Be(cm-1) =0.009 12; Re(Å) =5.2735. Possible correlation with the atomic limit 7 2P1/2+6 2S1/2 yields a dissociation energy De=4730±1 cm-1. [ABSTRACT FROM AUTHOR]