Normal Coordinates in the Methyl Halides

Abstract

The potential-energy functions found by Chang for the methyl halides have been put into valence-type form and revised to eliminate inconsistencies and to accord with the true (nontetrahedral) geometry and the normal frequencies (corrected for Fermi resonance and anharmonicity). The resulting valence-type force constants and normal coordinates are given for light (CH3) and heavy (CD3) chlorides, bromides, and iodides.