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The Far Infrared Spectrum of HOC1 Line Positions and Intensities



J.- M. Flaud, M Birk, G Wagner, J Orphal, S Klee, Walter J. Lafferty


The far infrared spectrum of HOC1 has been recorded at high resolution between 20 and 360 cm-1 by means of Fourier transform spectroscopy, and it was possible to observe pure rotation lines involving rotational levels with high Ka quantum numbers (up to Ka=9). These lines combined with microwave and tunable far infrared data available in the literature were least squares fitted using a Watson-type Hamiltonian. The fitting is excellent leading to precise sets of rotational and centrifugal distortion constants for the ground states of both isotopomers HO35C1 and HO37C1. Also relative line intensities were measured and their fitting allowed the determination of rotational corrections to the b-component of the permanent transition moment. Finally, in order to get for the (100),(010) and (001) vibrational states Hamiltonian constants consistent with the newly determined ground state constants, available data concerning the v1, v2 and v3 bands were refitted. Three interesting points are to be stressed. For the (001) state, we were able to complete the existing data with rotation lines observed in our spectra up to rather high Ka values (ka =7). For HO35C1, we were able to show that some (010) and (100) levels are perturbed by levels of the (002) and (030) states, respectively, through Coriolis-type interactions. This allows the determination of the band centers of these two dark states.
Journal of Molecular Spectroscopy


anharmonic interactions, far infrared spectrum, Hamiltonian constants, HOC1, hyperchlorous acid, rotational constants


Flaud, J. , Birk, M. , Wagner, G. , Orphal, J. , Klee, S. and Lafferty, W. (1998), The Far Infrared Spectrum of HOC1 Line Positions and Intensities, Journal of Molecular Spectroscopy (Accessed June 16, 2024)


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Created May 3, 1998, Updated October 12, 2021