10min:

XUEJUN WANG, J. YANG, J. B. QI AND A. M. LYYRA, Department of Physics, Temple University, Philadelphia, PA 19122; ROBERT J. LE ROY, Guelph-Waterloo Centre for Graduate Work in Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.

On combining our over 40 vibrational bands for the A\,¹_u⁺--X \, ¹_g⁺ system of ⁶Li_2\, and ^6,7Li_2\, sub-Doppler polarization spectrum with literature data from the Fourier transform spectrum of this system for ⁷Li_2\,, we have determined a new set of Le Roy - type molecular constants, which include mass-reduced Dunham constants and Born-Oppenheimer and JWKB breakdown (BOB) correction terms, describing these two electronic states of all three isotopomers. The preliminary results indicate that the BOB corrections are not significant for the X\,¹_g⁺ state, but are significant for A\,¹_u⁺ state.