Vibrations of Tetrahedral Pentatomic Molecules1. Part V. General Criteria for Potential Functions

The requirement that the forces along the bonds of the YX₄ molecule be fairly large as compared with "interaction forces" is shown to be sufficient to remove the ambiguity in the values of the constants in the potential energy function; no further special assumptions as to the types of forces involved are necessary. The ratio of the masses of the Y and X atoms determines in practically every case which set of force constants is the chemically acceptable one. Limiting values are given for the constant of the YX bond for CH₄, CCl₄, TiCl₄, SO₄^_^-, and other molecules. Wherever possible comparison is made between the limiting and the actual values.