LASER-INDUCED FLUORESCENCE SPECTROSCOPY OF THE B' 1(U)-X 0(G)(-2 - DETERMINATION OF THE B' STATE POTENTIAL AND EVIDENCE FOR A BARRIER TO DISSOCIATION() TRANSITION OF XE)

Ww report the observation of discrete and continuous laser induced flu orescence (LIF) spectra of th B' 1(u)-X 0(g)(+) transition of Xe-2, ne ar 68000 cm(-1). The discrete features continue 5 cm(-1) above the pre dicted atomic asymptote, which indicates the presence of a barrier to dissociation in the excited state. The dissociation (D'(e)=48+/-12 cm- 1), and excited state constants (r'(e)=5.46+.-0.05 Angstrom, w'(e)=5.9 +/-0.7 cm-1, and w(e)x'(e)=0.17+/-0.02 cm-1) for the B' state were obt ained from a Franck-Condon fit to the spectrum. The resulting potentia l is more shallow and has a longer equilibrium bond length compared wi th a previous experimentally derived potentia. The barrier to dissocia tion (2 cm-(1) less than or equal to h less than or equal to 10 cm(-1) , r approximate to 10 Angstrom) is attributed to the presence of a lon g-range (alpha 1/r(3)) repulsion, arising from a dipole-dipole resonan t interaction.