15min:

THOMAS A. BLAKE, ROBERT L. SAMS, Pacific Northwest National Laboratory, P. O. Box 999, Mail Stop K8-88, 3020 Q Avenue, Richland, WA 99352 (PNNL is operated for the US Department of Energy by the Battelle Memorial Institute under contract DE-AC06-76RLO 1830); ARTHUR MAKI, 15012 24th Ave. S. E. Mill Creek, WA 98012; TONY MASIELLO, JEFFREY BARBER, NICOLAE VULPANOVICI, ENGELENE T. H. CHRYSOSTOM, JOSEPH W. NIBLER, Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, OR 97331-4003; ALFONS WEBER, National Science Foundation, 4201 Wilson Boulevard, Arlington, VA 22230.

We are engaged in a comprehensive investigation of the fundamental and low lying combination and overtone bands of the parent ³²S¹⁶O₃ as well as the ³⁴S¹⁶O₃, ³²S¹⁸O₃, and ³⁴S¹⁸O₃ isotopic variants of sulfur trioxide. CARS spectroscopy of the ₁ Raman active bands has been performed at Oregon State University and high resolution infrared absorption spectroscopy of room temperature static cell samples has been performed at PNNL using a Bruker IFS 120 HR Fourier transform spectrometer. Results for the absorption spectrum of the 2 ₃ band of ³²S¹⁶O₃, recorded at a resolution of 0.0025 cm^-1, will be presented. The overtone of the ₃ fundamental [(e')² = A₁' + E'] is centered at 2777.87139(5) cm^-1 with B' = 0.3462802(2) cm^-1 and B'' = 0.34854336(4) cm^-1. Assignment and fitting of the perpendicular band shows that there is an internal perturbation that arises from a k = \pm2, l = \pm2 coupling of the l = 0 and l = \pm2 components. A level crossing is evident with the l = 2, k = 11 levels pushed to higher energy and the l = 2, k = 14 levels pushed to lower energy, for example. We have determined that the band center of the perturbing dark state is approximately 11 cm^-1 below that of the bright state. The Hamiltonian including perturbing terms and fit constants will be presented. In addition, ₂, ₃, and ₄ have been measured and analyzed to reveal new details such as the splitting of the K = 2 and K = 3 levels.