1. In early work, analytic expressions for the potential energy over the complete range of the displacement coordinates were attempted. There are several examples of central force models which were used for linear triatomic systems. P. Debye [Polar Molecules (Dover Publications, New York), p. 63 ff.] discusses near molecules in terms of central forces.
2. Earlier references to work of F. Hund and W. Heisenberg are given there. A. Adel and D. M. Dennison [Phys. Rev. 44, 99 (1933)] used an analytic central force potential in order to describe carbon dioxide without restriction to small amplitude displacements. PHRVAO0031-899X
3. Recently R. S. Berry [J. Chem. Phys. 30, 286 (1958)] has discussed the vibrations of the dihalides of group II metals in terms of a central force model.JCPSA60021-9606