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Interacting band analysis of the high-resolution spectrum of the 3nu/sub 3/ manifold of SF/sub 6/

Journal Article · · J. Mol. Spectrosc.; (United States)

The two infrared-active vibrational bands of the 3 nu/sub 3/ manifold of SF/sub 6/ have been recorded at T = 160 K with near Doppler-limited resolution using a tunable laser difference-frequency spectrometer. Most of the principal structure has been identified, and over 700 lines with J less than or equal to 33 have been fitted with a model Hamiltonian which allows the l - 1 and l = 3 subbands to interact. The analysis yields the values of ten spectroscopic constants. When earlier results for the nu/sub 3/ band are considered, the values of eight additional constants are derived. The effective harmonic frequency, ..omega../sup 0//sub 3/, and the three anharmonic coefficients X/sub 33/, G/sub 33/, and T/sub 33/, have been determined with high precision, so that the vibrational levels in the n nu/sub 3/ ladder can be predicted accurately for several values of n. The Cartesian basis (n/sub 3x/, n/sub 3y/, n/sub 3z/) is found to be the best representation for the vibrational sublevels. Analysis of the rovibrational line strengths reveals that the weak (2, 1, 0) band of 3 nu/sub 3/ has a very small intrinsic dipole transition moment, so that this band derives most of its intensity by borrowing from the strong (3, 0, 0) band.

OSTI ID:
6312641
Journal Information:
J. Mol. Spectrosc.; (United States), Journal Name: J. Mol. Spectrosc.; (United States) Vol. 88; ISSN JMOSA
Country of Publication:
United States
Language:
English