Vibrational dynamics of poly(L-glutamic acid) (β2 form)

The dispersion curves for β 2 sheet form of poly(L-glutamic acid) (PLG) are reported along with full normal coordinate analysis. Several earlier assignments have been revised. Characteristic features of the dispersion curves, such as repulsion, exchange of character etc., are discussed. Separate contributions to the heat capacity due to purely skeletal, pure side chain, and mix-modes have also been calculated via density-of-states. It is found that the maximum contribution comes from the mixed modes and minimum from the pure backbone modes.