CENTRIFUGAL CORRECTIONS TO ROTATIONAL INTENSITIES
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Date
1990
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Ohio State University
Abstract
Centrifugal corrections to rotational intensities for asymmetric rotors involve intensity borrowing from infrared transitions, as well as corrections to the rigid rotor wave functions. The latter type of correction is easily accomplished by using rotational programs that diagonalize the full rotational Hamiltonian instead of just the rigid rotor part. Intensity borrowing calculations require knowledge of the sign and magnitude of the infrared transition dipoles. Traditionally intensity corrections have been made using perturbation theory. The approach taken here is to directly diagonalize the Harmiltonian for the ground state and fundamentals using theoretical off-diagonal elements. When this calculation is used to refit the ground state energies, the resulting second order centrifucal constants should approach zero. In addition, the first order perturbations of the infrared intensities should be reproduced. It will be shown that effects of Watson indeterminancies and planarity conditions are accounted for in this type of calculation. Results of calculations for ozone and water will be shown. The calculations for water reproduce previously calculated corrections on the AFGL tapes, but corrections for ozone have not been done previously. Corrections for water range from 0.95 to 1.55, while corrections for ozone range from 0.78 to 1.25 However, the biggest corrections tend to be for the weaker lines
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Author Institution: Jet Propulsion Laboratory, California Institute of Technology