Normal mode analysis of syndiotactic polypropylene (T2G2T6G2) form

Syndiotactic polypropylene of all-trans form is transformed to (T2G2T6G2) form (new form) on exposing to xylene vapor under tension. This new form was characterized by infrared spectra and normal mode analysis. By increasing the gauche component from the all-trans to the new form, the infrared intensities of some bands increase. The potential energy distributions (PED) and L vectors for six monomers, which compose the repeating unit, were investigated. As a result, the PED and L vectors of the conformation-sensitive bands were found to be localized at the gauche position.