15min:
HIGH VIBRATIONAL LEVELS OF O2(b1 Sigmag+) AND O2(a1 Deltag).

K. S. KALOGERAKIS, D. L. HUESTIS, P. C. COSBY, T. G. SLANGER, R. A. COPELAND, Molecular Physics Laboratory, SRI International, Menlo Park, CA 94025; A. TOTTH, Bowdoin College, Brunswick, Me.

Relaxation of laser-excited O2(A3 Sigmau+,v=6-10) in collisions with O2 populates high vibrational levels of O2(b1 Sigmag+) and O2(a1 Deltag). Previous work on the spectroscopy of O2 emissions from the Earth's night atmosphere has enabled us to assign the Q-branches of thirteen (v',v") bands in the (2+1) REMPI spectra of O2(b1 Sigmag+, v"=10-15) and O2(a1 Deltag, v"=16-19), through the intermediate Rydberg levels 3d pi~1 Sigmag+(v'=2-5) and 1 Deltag(v'=4,5), repectively.

The derived spectroscopic constants for O2(b1 Sigmag+, v"=10-13) agree with our previous work. Improved values are obtained for v"=14,15. Our constants for 3d pi~1 Sigmag+(v'=5) are the first available. Our spectra are better calibrated and our constants for the v'=2-4 levels significantly more precise than the 1988-1992 work in the groups of Chupka and Houston.

The energies of O2(a1 Deltag, v"=16-19) were known previously only to within about 80~cm-1 from the 1995 electron scattering work of Allan. The highest level known accurately from nightglow spectra is v"=11. Our spectral analysis gives precise rotational constants and DeltaG values for these vibrational levels and for 3d pi~1 Deltag(v'=4,5). The absolute term energies are uncertain by about 5~cm-1 based on earlier work in the groups of Chupka and Houston.

Supported by the NASA Geospace Sciences and Planetary Atmospheres programs and by the NSF Aeronomy and Physics/REU programs.