A Representation of the Dynamic Properties of Molecules by Mechanical Models

Abstract

Mechanical models have been constructed to represent the dynamical systems believed to exist in the molecule. Assuming that the intramolecular forces lie along lines associated with the chemical bonds and that for small vibrations they obey Hooke's law and have the mechanical character of spiral springs, it is possible to get a picture of the forces and masses which can be represented on a large scale by steel balls and spiral springs. Models have been constructed for some of the simpler nonpolar molecules. They are found to have characteristic frequencies which correspond very closely to the frequencies observed in the Raman spectra, and it is possible by this means to identify the Raman lines with definite types of motion of particular atoms in the molecule. This substantiates the view that Raman lines correspond very closely to characteristic fundamental molecular frequencies.