15min:

ARTHUR MAKI, 15012 24th Ave. S.E., Mill Creek WA, 98012; TONY MASIELLO, THOMAS A. BLAKE, Pacific Northwest National Laboratory, P.O. Box 999, Mail Stop K8-88, Richland, WA 99352 (PNNL is operated for the US Department of Energy by the Battelle Memorial Institute under contract DE-AC05-76RL0 1830).

Last year at this Symposium (RX02) we presented spectroscopic measurements and ro-vibrational analysis for vibrational states of ¹¹BF₃ below 1600 cm^-1. This year we present measurements and analysis for vibrational states of ¹¹BF₃ up to 4300 cm^-1. Measurements were made of an isotopically enriched sample using a Bruker IFS 120HR Fourier transform spectrometer located at the Pacific Northwest National Laboratory. Spectra were recorded with resolutions ranging from 0.0015 to 0.0035 cm^-1 and pathlengths up to 32 m. The combination states in the following sets of interacting states have been either observed directly from a transition or determined indirectly by its perturbative affects on observed states: 102²0⁰ (3783.85162(8) cm^-1), 102⁰0⁰ (3756.085 cm^-1), 101^-13³ (3763.14(16) cm^-1), 002⁰2² (3830.233(50) cm^-1); 200⁰1¹ (2240.94976(3) cm^-1), 120⁰0⁰ (2264.327(10) cm^-1); 300⁰1¹ (3118.20602(6) cm^-1), 220⁰0⁰ (3141.688(13) cm^-1); 110⁰1¹ (2050.11053(7) cm^-1), 030⁰0⁰ (2081.12683(6) cm^-1); 010⁰2⁰ (1652.35840(7) cm^-1), 010⁰1² (1652.73764(5) cm^-1); 101¹0⁰ (2336.2009(29) cm^-1), 100⁰3^1,3 (2311.519(15) cm^-1); 201¹0⁰ (3216.2986(13) cm^-1), 200⁰3^1,3 (3188.650(76) cm^-1); (001¹1¹)^0,2 (1931.87377(14) cm^-1), (000⁰4^0,2,4) (1921.996(11) cm^-1); (101¹1¹)^0,2 (2810.69018(8) cm^-1), (100⁰4^0,2,4) (2787.31 cm^-1); (201¹1¹)^0,2 (3687.1503(10) cm^-1). The 003¹0⁰ - 000⁰0⁰ transition was observed near 4310 cm^-1 and was treated as an unperturbed perpendicular band except for the l -type resonance between the k =1, l =1 and k =-1, l =-1 levels. Effects from other perturbations are thought to be too small to be observed. An infrared forbidden transition 011¹0⁰ - 000⁰0⁰, E'' - A₁', was also observed near 2140 cm^-1. The transitions obey electric dipole allowed selection rules k =\pm2, l =\mp1. Intensity comes from a term in the dipole moment operator that governs the intensity of the 002²0⁰ - 000⁰0⁰ transition and to a lesser extent from terms that govern the intensity of the 001¹1¹ - 000⁰0⁰ transition and the fundamentals. A detailed discussion of the interactions and the fit spectroscopic constants will be presented for the vibrational states as well as the Hamiltonian used to derive them.