Ethylene vibrational force field

More Complicated Molecules.—Calculations have been reported on a number of more complicated molecules, as indicated in Table 4. The work on BFa and SOa, and on NH3 and NF3, is of particular interest since these are the simplest symmetric top structures for which the calculation is practical, and for which there exist sufficient spectroscopic data to make it worthwhile for symmetric top molecules there are extra observable vibration-rotation interaction constants associated with the vibrational degeneracy that provide further information on the force field (see Table 3). Formaldehyde and ethylene, and their simple halogen derivatives, and also methane, are obvious candidates for further work. 

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