Lattice dynamics deals with atomic vibrations in solids, and was first discussed in the early 1900's by Einstein who showed that the temperature dependence of a solid's heat capacity could be explained by the quantization of atomic vibrations. Over the next couple of decades this led to the development of the fundamental theory, however due to a lack of experimental evidence and the theories complexity, it wasn't until the 1960s with the advent of neutron scattering and computers that it began to be put to serious use.
