THE NU(1) AND NU(2) BANDS OF FNO2

High-resolution infrared spectra of the strong a-type absorptions corr esponding to the nu(1) (nu(0) similar to -1310.75 cm(-1)) and nu(2) (n u(0) = 821.9387 cm(-1)) bands of FNO2 have been analyzed. The nu(1) li ne positions exhibited extensive perturbations as a result of three ne arly degenerate vibrational states-nu(1), nu(3) + nu(6), and nu(5) + n u(6)-which interact through strong Coriolis coupling. The weak Corioli s interaction between nu(2) and nu(6) reported by Tanaka and Morino (1 969, J. Mol. Spectrosc. 32, 436-448) manifested itself through changes in the b-axis constants of the nu(2) = 1 state; nevertheless, over 14 00 nu(2) transitions were fit with an rms error of 0.00066 cm(-1) usin g the standard A-reduced Hamiltonian. Line positions, assignments, and relative intensities for the dominant transitions in both bands have been established, although a comprehensive analysis of the perturbatio ns requires a detailed understanding of the lower frequency vibrationa l states. (C) 1997 Academic Press.